Beaucoup de bonnes nouvelles et améliorations dans la prochaine version de PostgreSQL (v. 10) concernant les *hash index*. Tous les détails techniques ici.

## PostgreSQL 10 et les Hash Index

2 octobre 2017## SQL, problèmes et NULL!

2 octobre 2017## Les séquences démêlées pour vous

15 mars 2017Un excellent résumé qui fait un tour d’horizon des séquences (et des particularités de chacunes) pour les bases de données les plus populaires.

## MySQL en vrac (5)

16 février 2016Un sondage sur le déploiment et la gestion de bases de données *open source* ici.

On vous demande votre utilisation des *SQL Modes* ici.

Une présentation sur *PERFORMANCE_SCHEMA*.

La taille du *buffer pool* : quelques précisions ici.

L’allocation de mémoire des *buffers* pour le *performance schema* dans MySQL 5.7 : quelques conseils.

La perte de données au démarrage de MySQL : des explications.

## Bases de données et Pharo

4 avril 2015Un article datant de janvier mais qui reste d’actualité tant on peut constater un intérêt soudain et marqué pour Pharo 4 et les moyens de persister des données sur les *mailing lists* ces temps-ci.

## Enterprise NoSQL for Dummies

7 juillet 2014## Comment presser un citron (troisième partie)

27 mai 2013**1. Un problème n’arrive jamais seul**

Dans la deuxième partie de cet article (le premier article étant ici), nous nous sommes laissés sur un exemple extrême (i.e. une grille avec des lignes **et** des colonnes vides) afin de vérifier la validité et l’efficacité de la solution présentée dans un des pires scénarios envisageable :

Avant même de débuter, rappelez-vous qu’il est * primordial* d’exécuter la commande suivante dans votre session pour éviter d’avoir à attendre une éternité, que ce soit pour la requête SQL ou pour un EXPLAIN!

set @@optimizer_search_depth = 3;

Qu’arriverait-il si nous avions à solutionner un sudoku contenant à la fois des lignes et des colonnes vides, comme dans l’exemple ci-haut avec la requête suivante:

SELECT * FROM sudoku_combined_view WHERE (r2c2 = 3) AND (r2c3 = 4) AND (r2c4 = 8) AND (r2c5 = 2) AND (r2c6 = 5) AND (r2c7 = 6) AND (r2c8 = 9) AND (r3c2 = 5) AND (r3c3 = 9) AND (r3c4 = 3) AND (r3c5 = 6) AND (r3c6 = 4) AND (r3c7 = 1) AND (r3c8 = 8) AND (r4c2 = 9) AND (r4c3 = 7) AND (r4c4 = 1) AND (r4c5 = 8) AND (r4c6 = 2) AND (r4c7 = 5) AND (r4c8 = 6) AND (r6c2 = 8) AND (r6c3 = 1) AND (r6c4 = 4) AND (r6c5 = 7) AND (r6c6 = 6) AND (r6c7 = 2) AND (r6c8 = 3) AND (r7c2 = 2) AND (r7c3 = 5) AND (r7c4 = 6) AND (r7c5 = 4) AND (r7c6 = 1) AND (r7c7 = 9) AND (r7c8 = 7) AND (r8c2 = 7) AND (r8c3 = 6) AND (r8c4 = 5) AND (r8c5 = 3) AND (r8c6 = 8) AND (r8c7 = 4) AND (r8c8 = 2);

Examinons le résultat du EXPLAIN pour la grille en question:

+----+-------------+-------+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------+-------------+---------+-------------------------------+------+----------------------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------+-------------+---------+-------------------------------+------+----------------------------------------------------------+ | 1 | SIMPLE | col3 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i23,i38,i48 | 2,2,2 | NULL | 64 | Using intersect(i23,i38,i48); Using where | | 1 | SIMPLE | r2 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i23,i58 | 2,2 | NULL | 68 | Using intersect(i23,i58); Using where; Using join buffer | | 1 | SIMPLE | r3 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i78,i56 | 2,2 | NULL | 68 | Using intersect(i78,i56); Using where; Using join buffer | | 1 | SIMPLE | r4 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i38,i46 | 2,2 | NULL | 68 | Using intersect(i38,i46); Using where; Using join buffer | | 1 | SIMPLE | r6 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i23,i67 | 2,2 | NULL | 68 | Using intersect(i23,i67); Using where; Using join buffer | | 1 | SIMPLE | r7 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i38,i56 | 2,2 | NULL | 68 | Using intersect(i38,i56); Using where; Using join buffer | | 1 | SIMPLE | r8 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i23,i68 | 2,2 | NULL | 68 | Using intersect(i23,i68); Using where; Using join buffer | | 1 | SIMPLE | col2 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i23,i68 | 2,2 | NULL | 68 | Using intersect(i23,i68); Using where; Using join buffer | | 1 | SIMPLE | col4 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i78,i46 | 2,2 | NULL | 68 | Using intersect(i78,i46); Using where; Using join buffer | | 1 | SIMPLE | col5 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i23,i68 | 2,2 | NULL | 68 | Using intersect(i23,i68); Using where; Using join buffer | | 1 | SIMPLE | col6 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i23,i67 | 2,2 | NULL | 68 | Using intersect(i23,i67); Using where; Using join buffer | | 1 | SIMPLE | col7 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i23,i68 | 2,2 | NULL | 68 | Using intersect(i23,i68); Using where; Using join buffer | | 1 | SIMPLE | col8 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i37,i24 | 2,2 | NULL | 68 | Using intersect(i37,i24); Using where; Using join buffer | | 1 | SIMPLE | col1 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i23 | 2 | sudoku.r2.c1,sudoku.r3.c1 | 5040 | Using where | | 1 | SIMPLE | r1 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i12 | 2 | sudoku.col1.c1,sudoku.col2.c1 | 5040 | Using where | | 1 | SIMPLE | r5 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i12 | 2 | sudoku.col1.c5,sudoku.col2.c5 | 5040 | Using where | | 1 | SIMPLE | r9 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i12 | 2 | sudoku.col1.c9,sudoku.col2.c9 | 5040 | Using where | | 1 | SIMPLE | col9 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i12 | 2 | sudoku.r1.c9,sudoku.r2.c9 | 5040 | Using where | +----+-------------+-------+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------+-------------+---------+-------------------------------+------+----------------------------------------------------------+ 18 rows in set (0.20 sec)

À première vue, tout semble correct! Aucun *table scan *et les indexes sont utilisés pour chaque colonne et chaque rangée non vide!

Et en combien de temps MySQL peut-il « solutionner » cette grille ?

Fantastique! 1.5 seconde! Tout est réglé! Malheureusement, non…

**2. Le pire scénario possible**

Il existe une catégorie de sudokus que nombre de mathématiciens et d’informaticiens étudient depuis des années : ces grilles minimales n’ont seulement que 17 révélés, le minimum théorique (une conjecture encore non prouvée de façon mathématique par Gary McGuire, Bastian Tugemann et Gilles Civario, un autre intéressant article ici) pouvant mener à une solution unique. Plusieurs de ces grilles spéciales (17 révélés) sont depuis des années compilées par Gordon Royle, professeur à l’université d’Australie Occidentale.

Comme celle-ci :

Vous remarquerez que cette grille ne contient aucune ligne ni aucune colonne vide! Essayons donc de voir en combien de temps MySQL pourra résoudre celle-ci :

mysql> SELECT * -> FROM sudoku_combined_view -> WHERE -> (r1c8 = 1) AND -> (r2c1 = 4) AND -> (r3c2 = 2) AND -> (r4c5 = 5) AND -> (r4c7 = 4) AND -> (r4c9 = 7) AND -> (r5c3 = 8) AND -> (r5c7 = 3) AND -> (r6c3 = 1) AND -> (r6c5 = 9) AND -> (r7c1 = 3) AND -> (r7c4 = 4) AND -> (r7c7 = 2) AND -> (r8c2 = 5) AND -> (r8c4 = 1) AND -> (r9c4 = 8) AND -> (r9c6 = 6); +------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+ | r1c1 | r1c2 | r1c3 | r1c4 | r1c5 | r1c6 | r1c7 | r1c8 | r1c9 | r2c1 | r2c2 | r2c3 | r2c4 | r2c5 | r2c6 | r2c7 | r2c8 | r2c9 | r3c1 | r3c2 | r3c3 | r3c4 | r3c5 | r3c6 | r3c7 | r3c8 | r3c9 | r4c1 | r4c2 | r4c3 | r4c4 | r4c5 | r4c6 | r4c7 | r4c8 | r4c9 | r5c1 | r5c2 | r5c3 | r5c4 | r5c5 | r5c6 | r5c7 | r5c8 | r5c9 | r6c1 | r6c2 | r6c3 | r6c4 | r6c5 | r6c6 | r6c7 | r6c8 | r6c9 | r7c1 | r7c2 | r7c3 | r7c4 | r7c5 | r7c6 | r7c7 | r7c8 | r7c9 | r8c1 | r8c2 | r8c3 | r8c4 | r8c5 | r8c6 | r8c7 | r8c8 | r8c9 | r9c1 | r9c2 | r9c3 | r9c4 | r9c5 | r9c6 | r9c7 | r9c8 | r9c9 | +------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+ | 6 | 9 | 3 | 7 | 8 | 4 | 5 | 1 | 2 | 4 | 8 | 7 | 5 | 1 | 2 | 9 | 3 | 6 | 1 | 2 | 5 | 9 | 6 | 3 | 8 | 7 | 4 | 9 | 3 | 2 | 6 | 5 | 1 | 4 | 8 | 7 | 5 | 6 | 8 | 2 | 4 | 7 | 3 | 9 | 1 | 7 | 4 | 1 | 3 | 9 | 8 | 6 | 2 | 5 | 3 | 1 | 9 | 4 | 7 | 5 | 2 | 6 | 8 | 8 | 5 | 6 | 1 | 2 | 9 | 7 | 4 | 3 | 2 | 7 | 4 | 8 | 3 | 6 | 1 | 5 | 9 | +------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+ 1 row in set (2 min 20.83 sec)

Ouch! Je ne suis pas arrivé à descendre sour la barre des 40 secondes malgré mes tentatives répétées et ce, sur différents serveurs avec différentes configurations (et même différentes autres grilles de 17 révélés). Les résultats pour solutionner cette grille vont de près de 40 secondes à plus de 33 minutes. Le résultat du EXPLAIN parle par lui-même :

+----+-------------+-------+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------+---------+---------+-------------------------------+------+----------------------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------+---------+---------+-------------------------------+------+----------------------------------------------------------+ | 1 | SIMPLE | r4 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i57,i59 | 2,2 | NULL | 624 | Using intersect(i57,i59); Using where | | 1 | SIMPLE | r7 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i14,i47 | 2,2 | NULL | 624 | Using intersect(i14,i47); Using where; Using join buffer | | 1 | SIMPLE | col4 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i78,i89 | 2,2 | NULL | 624 | Using intersect(i78,i89); Using where; Using join buffer | | 1 | SIMPLE | col7 | index_merge | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i45,i47 | 2,2 | NULL | 624 | Using intersect(i45,i47); Using where; Using join buffer | | 1 | SIMPLE | r8 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i24 | 2 | const,const | 5000 | Using where | | 1 | SIMPLE | r9 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i46 | 2 | const,const | 5001 | Using where | | 1 | SIMPLE | col1 | range | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i27 | 2 | NULL | 5000 | Using where; Using join buffer | | 1 | SIMPLE | r5 | range | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i37 | 2 | NULL | 5001 | Using where; Using join buffer | | 1 | SIMPLE | r6 | range | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i35 | 2 | NULL | 5001 | Using where; Using join buffer | | 1 | SIMPLE | col3 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i45 | 2 | sudoku.r4.c3,const | 5040 | Using where | | 1 | SIMPLE | col2 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i34 | 2 | const,sudoku.r4.c2 | 5040 | Using where | | 1 | SIMPLE | r2 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i12 | 2 | const,sudoku.col2.c2 | 5040 | Using where | | 1 | SIMPLE | col5 | range | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i46 | 2 | NULL | 5001 | Using where; Using join buffer | | 1 | SIMPLE | r3 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i12 | 2 | sudoku.col1.c3,const | 5040 | Using where | | 1 | SIMPLE | col8 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i12 | 2 | const,sudoku.r2.c8 | 5040 | Using where | | 1 | SIMPLE | r1 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i12 | 2 | sudoku.col1.c1,sudoku.col2.c1 | 5040 | Using where | | 1 | SIMPLE | col9 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i12 | 2 | sudoku.r1.c9,sudoku.r2.c9 | 5040 | Using where | | 1 | SIMPLE | col6 | ref | i12,i13,i14,i15,i16,i17,i18,i19,i23,i24,i25,i26,i27,i28,i29,i34,i35,i36,i37,i38,i39,i45,i46,i47,i48,i49,i56,i57,i58,i59,i67,i68,i69,i78,i79,i89,i9 | i12 | 2 | sudoku.r1.c6,sudoku.r2.c6 | 5040 | Using where | +----+-------------+-------+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------+---------+---------+-------------------------------+------+----------------------------------------------------------+ 18 rows in set (2.59 sec)

Observez la colonne *rows *dans le résultat du EXPLAIN pour comprendre le nombre astronomique de jointures possibles que MySQL aura à effectuer et à tester… Dans la très grande majorité des cas, ce chiffre est supérieur à 5000!

Il devient maintenant évident que notre solution ne tient plus la route…

**3. Ne pas céder au découragement!**

Il existe bon nombre d’autres possibilités d’optimisations que nous n’avons toujours pas envisagées. Par exemple, dans certains cas il pourrait être avantageux de chercher par boîtes (carré de 3×3 dans le sudoku). Certaines grilles de 17 révélés pourraient grandement en bénéficier mais il nous faudrait alors joindre 27 tables! Ce qui est gagné d’un côté est perdu de l’autre.

Nous pourrions également créer des partitions mais dans ce cas, quelles seraient les chances qu’une colonne ou une rangée contienne la donnée permettant de discriminer et de choisir la partition requise?

Nous pourrions augmenter la taille de l’index pour passer de 2 colones à 3 mais l’impact de cette mesure serait inutile pour les grilles de 17 révélés.

Qu’arriverait-il si nous passions du format de table MyISAM à InnoDb ? Absolument rien, le problème demeure entier : MySQL n’est pas assez rapide pour lire les données (ou les indexes) sur disque puis les joindre efficacement dans un cas aussi extrême.

L’idée à la base de cette série d’article était d’arriver à solutionner un sudoku valide en n’utilisant que du SQL. Un sudoku valide, par définition, a une seule solution. Nous aurions pu ajouter LIMIT 1 à chacune de nos vues mais hélas, ce faisant, nos vues seraient contraintes d’utiliser l’algorithme TEMPTABLE au lieu de MERGE, ce qui serait catastrophique!

Évidemment, quelques autres astuces existent, comme augmenter la taille des variables *key_buffer_size* et *join_buffer_size*, diminuer la valeur du *optimizer_search_depth*, etc. Évidemment dans le cas des 2 premières variables, je ne peux rien vous suggérer comme ces paramètres dépendent de la mémoire RAM disponible sur votre machine, le système d’exploitation utilisé, etc. Quant à la valeur de la variable *optimizer_search_depth*, diminuer celle-ci n’aura pas d’impact significatif comme le problème réside dans la lenteur des accès au disque dur et au nombre effarant de jointures et de rangées à examnier (et à retrouver puis lire).

**4. Éplucher toutes les options**

Il existe un type de table, MEMORY, en MySQL qui nous permettrait d’éviter d’avoir à lire les données (ou les indexes) sur disque, ce qui pourrait avoir un impact majeur dans notre cas. Nous allons donc créer cette table en mémoire et la remplir tout en créant les indexes nécessaires (exactement les mêmes vues et indexes que la table de format MyISAM).

Mais avant de procéder, prenez bien soin de vous assurez que la variable **max_heap_table_size** soit supérieure à 216Mb ( 226492416) sinon vous vous heurterez à une tonne d’erreurs 1114 (*table full*). Si ce n’est pas le cas, vous pouvez fixer la valeur de cette variable à 216Mb comme suit :

set @@max_heap_table_size = 226492416;

Une fois cette précaution prise, construisez la table et les indexes nécessaires comme suit:

USE sudoku; DROP TABLE IF EXISTS positions_memory; CREATE TABLE positions_memory ( c1 TINYINT UNSIGNED NOT NULL, c2 TINYINT UNSIGNED NOT NULL, c3 TINYINT UNSIGNED NOT NULL, c4 TINYINT UNSIGNED NOT NULL, c5 TINYINT UNSIGNED NOT NULL, c6 TINYINT UNSIGNED NOT NULL, c7 TINYINT UNSIGNED NOT NULL, c8 TINYINT UNSIGNED NOT NULL, c9 TINYINT UNSIGNED NOT NULL ) ENGINE=MEMORY; INSERT INTO positions_memory (c1, c2, c3, c4, c5, c6, c7, c8, c9) SELECT c1, c2, c3, c4, c5, c6, c7, c8, c9 FROM positions; CREATE INDEX i12 ON positions_memory(c1, c2) USING HASH; CREATE INDEX i13 ON positions_memory(c1, c3) USING HASH; CREATE INDEX i14 ON positions_memory(c1, c4) USING HASH; CREATE INDEX i15 ON positions_memory(c1, c5) USING HASH; CREATE INDEX i16 ON positions_memory(c1, c6) USING HASH; CREATE INDEX i17 ON positions_memory(c1, c7) USING HASH; CREATE INDEX i18 ON positions_memory(c1, c8) USING HASH; CREATE INDEX i19 ON positions_memory(c1, c9) USING HASH; CREATE INDEX i23 ON positions_memory(c2, c3) USING HASH; CREATE INDEX i24 ON positions_memory(c2, c4) USING HASH; CREATE INDEX i25 ON positions_memory(c2, c5) USING HASH; CREATE INDEX i26 ON positions_memory(c2, c6) USING HASH; CREATE INDEX i27 ON positions_memory(c2, c7) USING HASH; CREATE INDEX i28 ON positions_memory(c2, c8) USING HASH; CREATE INDEX i29 ON positions_memory(c2, c9) USING HASH; CREATE INDEX i34 ON positions_memory(c3, c4) USING HASH; CREATE INDEX i35 ON positions_memory(c3, c5) USING HASH; CREATE INDEX i36 ON positions_memory(c3, c6) USING HASH; CREATE INDEX i37 ON positions_memory(c3, c7) USING HASH; CREATE INDEX i38 ON positions_memory(c3, c8) USING HASH; CREATE INDEX i39 ON positions_memory(c3, c9) USING HASH; CREATE INDEX i45 ON positions_memory(c4, c5) USING HASH; CREATE INDEX i46 ON positions_memory(c4, c6) USING HASH; CREATE INDEX i47 ON positions_memory(c4, c7) USING HASH; CREATE INDEX i48 ON positions_memory(c4, c8) USING HASH; CREATE INDEX i49 ON positions_memory(c4, c9) USING HASH; CREATE INDEX i56 ON positions_memory(c5, c6) USING HASH; CREATE INDEX i57 ON positions_memory(c5, c7) USING HASH; CREATE INDEX i58 ON positions_memory(c5, c8) USING HASH; CREATE INDEX i59 ON positions_memory(c5, c9) USING HASH; CREATE INDEX i67 ON positions_memory(c6, c7) USING HASH; CREATE INDEX i68 ON positions_memory(c6, c8) USING HASH; CREATE INDEX i69 ON positions_memory(c6, c9) USING HASH; CREATE INDEX i78 ON positions_memory(c7, c8) USING HASH; CREATE INDEX i79 ON positions_memory(c7, c9) USING HASH; CREATE INDEX i89 ON positions_memory(c8, c9) USING HASH; CREATE INDEX i9 ON positions_memory(c9) USING HASH;

Maintenant, il s’agit de recréer les trois mêmes vues que nous avons créées pour le type de table MYISAM mais pour notre nouvelle table.

En premier lieu, la vue sur les rangées.

USE sudoku; DROP VIEW IF EXISTS sudoku_memory_rows_view; CREATE VIEW sudoku_memory_rows_view AS SELECT r1.c1 as r1c1, r1.c2 as r1c2, r1.c3 as r1c3, r1.c4 as r1c4, r1.c5 as r1c5, r1.c6 as r1c6, r1.c7 as r1c7, r1.c8 as r1c8, r1.c9 as r1c9, r2.c1 as r2c1, r2.c2 as r2c2, r2.c3 as r2c3, r2.c4 as r2c4, r2.c5 as r2c5, r2.c6 as r2c6, r2.c7 as r2c7, r2.c8 as r2c8, r2.c9 as r2c9, r3.c1 as r3c1, r3.c2 as r3c2, r3.c3 as r3c3, r3.c4 as r3c4, r3.c5 as r3c5, r3.c6 as r3c6, r3.c7 as r3c7, r3.c8 as r3c8, r3.c9 as r3c9, r4.c1 as r4c1, r4.c2 as r4c2, r4.c3 as r4c3, r4.c4 as r4c4, r4.c5 as r4c5, r4.c6 as r4c6, r4.c7 as r4c7, r4.c8 as r4c8, r4.c9 as r4c9, r5.c1 as r5c1, r5.c2 as r5c2, r5.c3 as r5c3, r5.c4 as r5c4, r5.c5 as r5c5, r5.c6 as r5c6, r5.c7 as r5c7, r5.c8 as r5c8, r5.c9 as r5c9, r6.c1 as r6c1, r6.c2 as r6c2, r6.c3 as r6c3, r6.c4 as r6c4, r6.c5 as r6c5, r6.c6 as r6c6, r6.c7 as r6c7, r6.c8 as r6c8, r6.c9 as r6c9, r7.c1 as r7c1, r7.c2 as r7c2, r7.c3 as r7c3, r7.c4 as r7c4, r7.c5 as r7c5, r7.c6 as r7c6, r7.c7 as r7c7, r7.c8 as r7c8, r7.c9 as r7c9, r8.c1 as r8c1, r8.c2 as r8c2, r8.c3 as r8c3, r8.c4 as r8c4, r8.c5 as r8c5, r8.c6 as r8c6, r8.c7 as r8c7, r8.c8 as r8c8, r8.c9 as r8c9, r9.c1 as r9c1, r9.c2 as r9c2, r9.c3 as r9c3, r9.c4 as r9c4, r9.c5 as r9c5, r9.c6 as r9c6, r9.c7 as r9c7, r9.c8 as r9c8, r9.c9 as r9c9 FROM positions_memory r1, positions_memory r2, positions_memory r3, positions_memory r4, positions_memory r5, positions_memory r6, positions_memory r7, positions_memory r8, positions_memory r9 WHERE -- Nombres uniques dans chaque colonne (r1.c1 <> r2.c1) AND (r1.c1 <> r3.c1) AND (r1.c1 <> r4.c1) AND (r1.c1 <> r5.c1) AND (r1.c1 <> r6.c1) AND (r1.c1 <> r7.c1) AND (r1.c1 <> r8.c1) AND (r1.c1 <> r9.c1) AND (r1.c2 <> r2.c2) AND (r1.c2 <> r3.c2) AND (r1.c2 <> r4.c2) AND (r1.c2 <> r5.c2) AND (r1.c2 <> r6.c2) AND (r1.c2 <> r7.c2) AND (r1.c2 <> r8.c2) AND (r1.c2 <> r9.c2) AND (r1.c3 <> r2.c3) AND (r1.c3 <> r3.c3) AND (r1.c3 <> r4.c3) AND (r1.c3 <> r5.c3) AND (r1.c3 <> r6.c3) AND (r1.c3 <> r7.c3) AND (r1.c3 <> r8.c3) AND (r1.c3 <> r9.c3) AND (r1.c4 <> r2.c4) AND (r1.c4 <> r3.c4) AND (r1.c4 <> r4.c4) AND (r1.c4 <> r5.c4) AND (r1.c4 <> r6.c4) AND (r1.c4 <> r7.c4) AND (r1.c4 <> r8.c4) AND (r1.c4 <> r9.c4) AND (r1.c5 <> r2.c5) AND (r1.c5 <> r3.c5) AND (r1.c5 <> r4.c5) AND (r1.c5 <> r5.c5) AND (r1.c5 <> r6.c5) AND (r1.c5 <> r7.c5) AND (r1.c5 <> r8.c5) AND (r1.c5 <> r9.c5) AND (r1.c6 <> r2.c6) AND (r1.c6 <> r3.c6) AND (r1.c6 <> r4.c6) AND (r1.c6 <> r5.c6) AND (r1.c6 <> r6.c6) AND (r1.c6 <> r7.c6) AND (r1.c6 <> r8.c6) AND (r1.c6 <> r9.c6) AND (r1.c7 <> r2.c7) AND (r1.c7 <> r3.c7) AND (r1.c7 <> r4.c7) AND (r1.c7 <> r5.c7) AND (r1.c7 <> r6.c7) AND (r1.c7 <> r7.c7) AND (r1.c7 <> r8.c7) AND (r1.c7 <> r9.c7) AND (r1.c8 <> r2.c8) AND (r1.c8 <> r3.c8) AND (r1.c8 <> r4.c8) AND (r1.c8 <> r5.c8) AND (r1.c8 <> r6.c8) AND (r1.c8 <> r7.c8) AND (r1.c8 <> r8.c8) AND (r1.c8 <> r9.c8) AND (r1.c9 <> r2.c9) AND (r1.c9 <> r3.c9) AND (r1.c9 <> r4.c9) AND (r1.c9 <> r5.c9) AND (r1.c9 <> r6.c9) AND (r1.c9 <> r7.c9) AND (r1.c9 <> r8.c9) AND (r1.c9 <> r9.c9) AND (r2.c1 <> r3.c1) AND (r2.c1 <> r4.c1) AND (r2.c1 <> r5.c1) AND (r2.c1 <> r6.c1) AND (r2.c1 <> r7.c1) AND (r2.c1 <> r8.c1) AND (r2.c1 <> r9.c1) AND (r2.c2 <> r3.c2) AND (r2.c2 <> r4.c2) AND (r2.c2 <> r5.c2) AND (r2.c2 <> r6.c2) AND (r2.c2 <> r7.c2) AND (r2.c2 <> r8.c2) AND (r2.c2 <> r9.c2) AND (r2.c3 <> r3.c3) AND (r2.c3 <> r4.c3) AND (r2.c3 <> r5.c3) AND (r2.c3 <> r6.c3) AND (r2.c3 <> r7.c3) AND (r2.c3 <> r8.c3) AND (r2.c3 <> r9.c3) AND (r2.c4 <> r3.c4) AND (r2.c4 <> r4.c4) AND (r2.c4 <> r5.c4) AND (r2.c4 <> r6.c4) AND (r2.c4 <> r7.c4) AND (r2.c4 <> r8.c4) AND (r2.c4 <> r9.c4) AND (r2.c5 <> r3.c5) AND (r2.c5 <> r4.c5) AND (r2.c5 <> r5.c5) AND (r2.c5 <> r6.c5) AND (r2.c5 <> r7.c5) AND (r2.c5 <> r8.c5) AND (r2.c5 <> r9.c5) AND (r2.c6 <> r3.c6) AND (r2.c6 <> r4.c6) AND (r2.c6 <> r5.c6) AND (r2.c6 <> r6.c6) AND (r2.c6 <> r7.c6) AND (r2.c6 <> r8.c6) AND (r2.c6 <> r9.c6) AND (r2.c7 <> r3.c7) AND (r2.c7 <> r4.c7) AND (r2.c7 <> r5.c7) AND (r2.c7 <> r6.c7) AND (r2.c7 <> r7.c7) AND (r2.c7 <> r8.c7) AND (r2.c7 <> r9.c7) AND (r2.c8 <> r3.c8) AND (r2.c8 <> r4.c8) AND (r2.c8 <> r5.c8) AND (r2.c8 <> r6.c8) AND (r2.c8 <> r7.c8) AND (r2.c8 <> r8.c8) AND (r2.c8 <> r9.c8) AND (r2.c9 <> r3.c9) AND (r2.c9 <> r4.c9) AND (r2.c9 <> r5.c9) AND (r2.c9 <> r6.c9) AND (r2.c9 <> r7.c9) AND (r2.c9 <> r8.c9) AND (r2.c9 <> r9.c9) AND (r3.c1 <> r4.c1) AND (r3.c1 <> r5.c1) AND (r3.c1 <> r6.c1) AND (r3.c1 <> r7.c1) AND (r3.c1 <> r8.c1) AND (r3.c1 <> r9.c1) AND (r3.c2 <> r4.c2) AND (r3.c2 <> r5.c2) AND (r3.c2 <> r6.c2) AND (r3.c2 <> r7.c2) AND (r3.c2 <> r8.c2) AND (r3.c2 <> r9.c2) AND (r3.c3 <> r4.c3) AND (r3.c3 <> r5.c3) AND (r3.c3 <> r6.c3) AND (r3.c3 <> r7.c3) AND (r3.c3 <> r8.c3) AND (r3.c3 <> r9.c3) AND (r3.c4 <> r4.c4) AND (r3.c4 <> r5.c4) AND (r3.c4 <> r6.c4) AND (r3.c4 <> r7.c4) AND (r3.c4 <> r8.c4) AND (r3.c4 <> r9.c4) AND (r3.c5 <> r4.c5) AND (r3.c5 <> r5.c5) AND (r3.c5 <> r6.c5) AND (r3.c5 <> r7.c5) AND (r3.c5 <> r8.c5) AND (r3.c5 <> r9.c5) AND (r3.c6 <> r4.c6) AND (r3.c6 <> r5.c6) AND (r3.c6 <> r6.c6) AND (r3.c6 <> r7.c6) AND (r3.c6 <> r8.c6) AND (r3.c6 <> r9.c6) AND (r3.c7 <> r4.c7) AND (r3.c7 <> r5.c7) AND (r3.c7 <> r6.c7) AND (r3.c7 <> r7.c7) AND (r3.c7 <> r8.c7) AND (r3.c7 <> r9.c7) AND (r3.c8 <> r4.c8) AND (r3.c8 <> r5.c8) AND (r3.c8 <> r6.c8) AND (r3.c8 <> r7.c8) AND (r3.c8 <> r8.c8) AND (r3.c8 <> r9.c8) AND (r3.c9 <> r4.c9) AND (r3.c9 <> r5.c9) AND (r3.c9 <> r6.c9) AND (r3.c9 <> r7.c9) AND (r3.c9 <> r8.c9) AND (r3.c9 <> r9.c9) AND (r4.c1 <> r5.c1) AND (r4.c1 <> r6.c1) AND (r4.c1 <> r7.c1) AND (r4.c1 <> r8.c1) AND (r4.c1 <> r9.c1) AND (r4.c2 <> r5.c2) AND (r4.c2 <> r6.c2) AND (r4.c2 <> r7.c2) AND (r4.c2 <> r8.c2) AND (r4.c2 <> r9.c2) AND (r4.c3 <> r5.c3) AND (r4.c3 <> r6.c3) AND (r4.c3 <> r7.c3) AND (r4.c3 <> r8.c3) AND (r4.c3 <> r9.c3) AND (r4.c4 <> r5.c4) AND (r4.c4 <> r6.c4) AND (r4.c4 <> r7.c4) AND (r4.c4 <> r8.c4) AND (r4.c4 <> r9.c4) AND (r4.c5 <> r5.c5) AND (r4.c5 <> r6.c5) AND (r4.c5 <> r7.c5) AND (r4.c5 <> r8.c5) AND (r4.c5 <> r9.c5) AND (r4.c6 <> r5.c6) AND (r4.c6 <> r6.c6) AND (r4.c6 <> r7.c6) AND (r4.c6 <> r8.c6) AND (r4.c6 <> r9.c6) AND (r4.c7 <> r5.c7) AND (r4.c7 <> r6.c7) AND (r4.c7 <> r7.c7) AND (r4.c7 <> r8.c7) AND (r4.c7 <> r9.c7) AND (r4.c8 <> r5.c8) AND (r4.c8 <> r6.c8) AND (r4.c8 <> r7.c8) AND (r4.c8 <> r8.c8) AND (r4.c8 <> r9.c8) AND (r4.c9 <> r5.c9) AND (r4.c9 <> r6.c9) AND (r4.c9 <> r7.c9) AND (r4.c9 <> r8.c9) AND (r4.c9 <> r9.c9) AND (r5.c1 <> r6.c1) AND (r5.c1 <> r7.c1) AND (r5.c1 <> r8.c1) AND (r5.c1 <> r9.c1) AND (r5.c2 <> r6.c2) AND (r5.c2 <> r7.c2) AND (r5.c2 <> r8.c2) AND (r5.c2 <> r9.c2) AND (r5.c3 <> r6.c3) AND (r5.c3 <> r7.c3) AND (r5.c3 <> r8.c3) AND (r5.c3 <> r9.c3) AND (r5.c4 <> r6.c4) AND (r5.c4 <> r7.c4) AND (r5.c4 <> r8.c4) AND (r5.c4 <> r9.c4) AND (r5.c5 <> r6.c5) AND (r5.c5 <> r7.c5) AND (r5.c5 <> r8.c5) AND (r5.c5 <> r9.c5) AND (r5.c6 <> r6.c6) AND (r5.c6 <> r7.c6) AND (r5.c6 <> r8.c6) AND (r5.c6 <> r9.c6) AND (r5.c7 <> r6.c7) AND (r5.c7 <> r7.c7) AND (r5.c7 <> r8.c7) AND (r5.c7 <> r9.c7) AND (r5.c8 <> r6.c8) AND (r5.c8 <> r7.c8) AND (r5.c8 <> r8.c8) AND (r5.c8 <> r9.c8) AND (r5.c9 <> r6.c9) AND (r5.c9 <> r7.c9) AND (r5.c9 <> r8.c9) AND (r5.c9 <> r9.c9) AND (r6.c1 <> r7.c1) AND (r6.c1 <> r8.c1) AND (r6.c1 <> r9.c1) AND (r6.c2 <> r7.c2) AND (r6.c2 <> r8.c2) AND (r6.c2 <> r9.c2) AND (r6.c3 <> r7.c3) AND (r6.c3 <> r8.c3) AND (r6.c3 <> r9.c3) AND (r6.c4 <> r7.c4) AND (r6.c4 <> r8.c4) AND (r6.c4 <> r9.c4) AND (r6.c5 <> r7.c5) AND (r6.c5 <> r8.c5) AND (r6.c5 <> r9.c5) AND (r6.c6 <> r7.c6) AND (r6.c6 <> r8.c6) AND (r6.c6 <> r9.c6) AND (r6.c7 <> r7.c7) AND (r6.c7 <> r8.c7) AND (r6.c7 <> r9.c7) AND (r6.c8 <> r7.c8) AND (r6.c8 <> r8.c8) AND (r6.c8 <> r9.c8) AND (r6.c9 <> r7.c9) AND (r6.c9 <> r8.c9) AND (r6.c9 <> r9.c9) AND (r7.c1 <> r8.c1) AND (r7.c1 <> r9.c1) AND (r7.c2 <> r8.c2) AND (r7.c2 <> r9.c2) AND (r7.c3 <> r8.c3) AND (r7.c3 <> r9.c3) AND (r7.c4 <> r8.c4) AND (r7.c4 <> r9.c4) AND (r7.c5 <> r8.c5) AND (r7.c5 <> r9.c5) AND (r7.c6 <> r8.c6) AND (r7.c6 <> r9.c6) AND (r7.c7 <> r8.c7) AND (r7.c7 <> r9.c7) AND (r7.c8 <> r8.c8) AND (r7.c8 <> r9.c8) AND (r7.c9 <> r8.c9) AND (r7.c9 <> r9.c9) AND (r8.c1 <> r9.c1) AND (r8.c2 <> r9.c2) AND (r8.c3 <> r9.c3) AND (r8.c4 <> r9.c4) AND (r8.c5 <> r9.c5) AND (r8.c6 <> r9.c6) AND (r8.c7 <> r9.c7) AND (r8.c8 <> r9.c8) AND (r8.c9 <> r9.c9) AND -- Nombres uniques dans chaque maison de 3x3 (r1.c1 <> r2.c2) AND (r1.c1 <> r2.c3) AND (r1.c1 <> r3.c2) AND (r1.c1 <> r3.c3) AND (r1.c2 <> r2.c1) AND (r1.c2 <> r2.c3) AND (r1.c2 <> r3.c1) AND (r1.c2 <> r3.c3) AND (r1.c3 <> r2.c1) AND (r1.c3 <> r2.c2) AND (r1.c3 <> r3.c1) AND (r1.c3 <> r3.c2) AND (r1.c4 <> r2.c5) AND (r1.c4 <> r2.c6) AND (r1.c4 <> r3.c5) AND (r1.c4 <> r3.c6) AND (r1.c5 <> r2.c4) AND (r1.c5 <> r2.c6) AND (r1.c5 <> r3.c4) AND (r1.c5 <> r3.c6) AND (r1.c6 <> r2.c4) AND (r1.c6 <> r2.c5) AND (r1.c6 <> r3.c4) AND (r1.c6 <> r3.c5) AND (r1.c7 <> r2.c8) AND (r1.c7 <> r2.c9) AND (r1.c7 <> r3.c8) AND (r1.c7 <> r3.c9) AND (r1.c8 <> r2.c7) AND (r1.c8 <> r2.c9) AND (r1.c8 <> r3.c7) AND (r1.c8 <> r3.c9) AND (r1.c9 <> r2.c7) AND (r1.c9 <> r2.c8) AND (r1.c9 <> r3.c7) AND (r1.c9 <> r3.c8) AND (r2.c1 <> r3.c2) AND (r2.c1 <> r3.c3) AND (r2.c2 <> r3.c1) AND (r2.c2 <> r3.c3) AND (r2.c3 <> r3.c1) AND (r2.c3 <> r3.c2) AND (r2.c4 <> r3.c5) AND (r2.c4 <> r3.c6) AND (r2.c5 <> r3.c4) AND (r2.c5 <> r3.c6) AND (r2.c6 <> r3.c4) AND (r2.c6 <> r3.c5) AND (r2.c7 <> r3.c8) AND (r2.c7 <> r3.c9) AND (r2.c8 <> r3.c7) AND (r2.c8 <> r3.c9) AND (r2.c9 <> r3.c7) AND (r2.c9 <> r3.c8) AND (r4.c1 <> r5.c2) AND (r4.c1 <> r5.c3) AND (r4.c1 <> r6.c2) AND (r4.c1 <> r6.c3) AND (r4.c2 <> r5.c1) AND (r4.c2 <> r5.c3) AND (r4.c2 <> r6.c1) AND (r4.c2 <> r6.c3) AND (r4.c3 <> r5.c1) AND (r4.c3 <> r5.c2) AND (r4.c3 <> r6.c1) AND (r4.c3 <> r6.c2) AND (r4.c4 <> r5.c5) AND (r4.c4 <> r5.c6) AND (r4.c4 <> r6.c5) AND (r4.c4 <> r6.c6) AND (r4.c5 <> r5.c4) AND (r4.c5 <> r5.c6) AND (r4.c5 <> r6.c4) AND (r4.c5 <> r6.c6) AND (r4.c6 <> r5.c4) AND (r4.c6 <> r5.c5) AND (r4.c6 <> r6.c4) AND (r4.c6 <> r6.c5) AND (r4.c7 <> r5.c8) AND (r4.c7 <> r5.c9) AND (r4.c7 <> r6.c8) AND (r4.c7 <> r6.c9) AND (r4.c8 <> r5.c7) AND (r4.c8 <> r5.c9) AND (r4.c8 <> r6.c7) AND (r4.c8 <> r6.c9) AND (r4.c9 <> r5.c7) AND (r4.c9 <> r5.c8) AND (r4.c9 <> r6.c7) AND (r4.c9 <> r6.c8) AND (r5.c1 <> r6.c2) AND (r5.c1 <> r6.c3) AND (r5.c2 <> r6.c1) AND (r5.c2 <> r6.c3) AND (r5.c3 <> r6.c1) AND (r5.c3 <> r6.c2) AND (r5.c4 <> r6.c5) AND (r5.c4 <> r6.c6) AND (r5.c5 <> r6.c4) AND (r5.c5 <> r6.c6) AND (r5.c6 <> r6.c4) AND (r5.c6 <> r6.c5) AND (r5.c7 <> r6.c8) AND (r5.c7 <> r6.c9) AND (r5.c8 <> r6.c7) AND (r5.c8 <> r6.c9) AND (r5.c9 <> r6.c7) AND (r5.c9 <> r6.c8) AND (r7.c1 <> r8.c2) AND (r7.c1 <> r8.c3) AND (r7.c1 <> r9.c2) AND (r7.c1 <> r9.c3) AND (r7.c2 <> r8.c1) AND (r7.c2 <> r8.c3) AND (r7.c2 <> r9.c1) AND (r7.c2 <> r9.c3) AND (r7.c3 <> r8.c1) AND (r7.c3 <> r8.c2) AND (r7.c3 <> r9.c1) AND (r7.c3 <> r9.c2) AND (r7.c4 <> r8.c5) AND (r7.c4 <> r8.c6) AND (r7.c4 <> r9.c5) AND (r7.c4 <> r9.c6) AND (r7.c5 <> r8.c4) AND (r7.c5 <> r8.c6) AND (r7.c5 <> r9.c4) AND (r7.c5 <> r9.c6) AND (r7.c6 <> r8.c4) AND (r7.c6 <> r8.c5) AND (r7.c6 <> r9.c4) AND (r7.c6 <> r9.c5) AND (r7.c7 <> r8.c8) AND (r7.c7 <> r8.c9) AND (r7.c7 <> r9.c8) AND (r7.c7 <> r9.c9) AND (r7.c8 <> r8.c7) AND (r7.c8 <> r8.c9) AND (r7.c8 <> r9.c7) AND (r7.c8 <> r9.c9) AND (r7.c9 <> r8.c7) AND (r7.c9 <> r8.c8) AND (r7.c9 <> r9.c7) AND (r7.c9 <> r9.c8) AND (r8.c1 <> r9.c2) AND (r8.c1 <> r9.c3) AND (r8.c2 <> r9.c1) AND (r8.c2 <> r9.c3) AND (r8.c3 <> r9.c1) AND (r8.c3 <> r9.c2) AND (r8.c4 <> r9.c5) AND (r8.c4 <> r9.c6) AND (r8.c5 <> r9.c4) AND (r8.c5 <> r9.c6) AND (r8.c6 <> r9.c4) AND (r8.c6 <> r9.c5) AND (r8.c7 <> r9.c8) AND (r8.c7 <> r9.c9) AND (r8.c8 <> r9.c7) AND (r8.c8 <> r9.c9) AND (r8.c9 <> r9.c7) AND (r8.c9 <> r9.c8);

En second lieu, la vue sur les colonnes.

USE sudoku; DROP VIEW IF EXISTS sudoku_memory_columns_view; CREATE VIEW sudoku_memory_columns_view AS SELECT col1.c1 as r1c1, col1.c2 as r2c1, col1.c3 as r3c1, col1.c4 as r4c1, col1.c5 as r5c1,col1.c6 as r6c1, col1.c7 as r7c1, col1.c8 as r8c1, col1.c9 as r9c1, col2.c1 as r1c2, col2.c2 as r2c2, col2.c3 as r3c2, col2.c4 as r4c2, col2.c5 as r5c2, col2.c6 as r6c2,col2.c7 as r7c2, col2.c8 as r8c2, col2.c9 as r9c2, col3.c1 as r1c3, col3.c2 as r2c3, col3.c3 as r3c3, col3.c4 as r4c3, col3.c5 as r5c3, col3.c6 as r6c3, col3.c7 as r7c3,col3.c8 as r8c3, col3.c9 as r9c3, col4.c1 as r1c4, col4.c2 as r2c4, col4.c3 as r3c4, col4.c4 as r4c4, col4.c5 as r5c4, col4.c6 as r6c4, col4.c7 as r7c4, col4.c8 as r8c4,col4.c9 as r9c4, col5.c1 as r1c5, col5.c2 as r2c5, col5.c3 as r3c5, col5.c4 as r4c5, col5.c5 as r5c5, col5.c6 as r6c5, col5.c7 as r7c5, col5.c8 as r8c5, col5.c9 as r9c5,col6.c1 as r1c6, col6.c2 as r2c6, col6.c3 as r3c6, col6.c4 as r4c6, col6.c5 as r5c6, col6.c6 as r6c6, col6.c7 as r7c6, col6.c8 as r8c6, col6.c9 as r9c6, col7.c1 as r1c7,col7.c2 as r2c7, col7.c3 as r3c7, col7.c4 as r4c7, col7.c5 as r5c7, col7.c6 as r6c7, col7.c7 as r7c7, col7.c8 as r8c7, col7.c9 as r9c7, col8.c1 as r1c8, col8.c2 as r2c8,col8.c3 as r3c8, col8.c4 as r4c8, col8.c5 as r5c8, col8.c6 as r6c8, col8.c7 as r7c8, col8.c8 as r8c8, col8.c9 as r9c8, col9.c1 as r1c9, col9.c2 as r2c9, col9.c3 as r3c9,col9.c4 as r4c9, col9.c5 as r5c9, col9.c6 as r6c9, col9.c7 as r7c9, col9.c8 as r8c9, col9.c9 as r9c9 FROM positions_memory col1, positions_memory col2, positions_memory col3, positions_memory col4, positions_memory col5, positions_memory col6, positions_memory col7, positions_memory col8, positions_memory col9 WHERE -- Nombres uniques dans chaque rangee (col1.c1 <> col2.c1) AND (col1.c1 <> col3.c1) AND (col1.c1 <> col4.c1) AND (col1.c1 <> col5.c1) AND (col1.c1 <> col6.c1) AND (col1.c1 <> col7.c1) AND (col1.c1 <> col8.c1) AND (col1.c1 <> col9.c1) AND (col1.c2 <> col2.c2) AND (col1.c2 <> col3.c2) AND (col1.c2 <> col4.c2) AND (col1.c2 <> col5.c2) AND (col1.c2 <> col6.c2) AND (col1.c2 <> col7.c2) AND (col1.c2 <> col8.c2) AND (col1.c2 <> col9.c2) AND (col1.c3 <> col2.c3) AND (col1.c3 <> col3.c3) AND (col1.c3 <> col4.c3) AND (col1.c3 <> col5.c3) AND (col1.c3 <> col6.c3) AND (col1.c3 <> col7.c3) AND (col1.c3 <> col8.c3) AND (col1.c3 <> col9.c3) AND (col1.c4 <> col2.c4) AND (col1.c4 <> col3.c4) AND (col1.c4 <> col4.c4) AND (col1.c4 <> col5.c4) AND (col1.c4 <> col6.c4) AND (col1.c4 <> col7.c4) AND (col1.c4 <> col8.c4) AND (col1.c4 <> col9.c4) AND (col1.c5 <> col2.c5) AND (col1.c5 <> col3.c5) AND (col1.c5 <> col4.c5) AND (col1.c5 <> col5.c5) AND (col1.c5 <> col6.c5) AND (col1.c5 <> col7.c5) AND (col1.c5 <> col8.c5) AND (col1.c5 <> col9.c5) AND (col1.c6 <> col2.c6) AND (col1.c6 <> col3.c6) AND (col1.c6 <> col4.c6) AND (col1.c6 <> col5.c6) AND (col1.c6 <> col6.c6) AND (col1.c6 <> col7.c6) AND (col1.c6 <> col8.c6) AND (col1.c6 <> col9.c6) AND (col1.c7 <> col2.c7) AND (col1.c7 <> col3.c7) AND (col1.c7 <> col4.c7) AND (col1.c7 <> col5.c7) AND (col1.c7 <> col6.c7) AND (col1.c7 <> col7.c7) AND (col1.c7 <> col8.c7) AND (col1.c7 <> col9.c7) AND (col1.c8 <> col2.c8) AND (col1.c8 <> col3.c8) AND (col1.c8 <> col4.c8) AND (col1.c8 <> col5.c8) AND (col1.c8 <> col6.c8) AND (col1.c8 <> col7.c8) AND (col1.c8 <> col8.c8) AND (col1.c8 <> col9.c8) AND (col1.c9 <> col2.c9) AND (col1.c9 <> col3.c9) AND (col1.c9 <> col4.c9) AND (col1.c9 <> col5.c9) AND (col1.c9 <> col6.c9) AND (col1.c9 <> col7.c9) AND (col1.c9 <> col8.c9) AND (col1.c9 <> col9.c9) AND (col2.c1 <> col3.c1) AND (col2.c1 <> col4.c1) AND (col2.c1 <> col5.c1) AND (col2.c1 <> col6.c1) AND (col2.c1 <> col7.c1) AND (col2.c1 <> col8.c1) AND (col2.c1 <> col9.c1) AND (col2.c2 <> col3.c2) AND (col2.c2 <> col4.c2) AND (col2.c2 <> col5.c2) AND (col2.c2 <> col6.c2) AND (col2.c2 <> col7.c2) AND (col2.c2 <> col8.c2) AND (col2.c2 <> col9.c2) AND (col2.c3 <> col3.c3) AND (col2.c3 <> col4.c3) AND (col2.c3 <> col5.c3) AND (col2.c3 <> col6.c3) AND (col2.c3 <> col7.c3) AND (col2.c3 <> col8.c3) AND (col2.c3 <> col9.c3) AND (col2.c4 <> col3.c4) AND (col2.c4 <> col4.c4) AND (col2.c4 <> col5.c4) AND (col2.c4 <> col6.c4) AND (col2.c4 <> col7.c4) AND (col2.c4 <> col8.c4) AND (col2.c4 <> col9.c4) AND (col2.c5 <> col3.c5) AND (col2.c5 <> col4.c5) AND (col2.c5 <> col5.c5) AND (col2.c5 <> col6.c5) AND (col2.c5 <> col7.c5) AND (col2.c5 <> col8.c5) AND (col2.c5 <> col9.c5) AND (col2.c6 <> col3.c6) AND (col2.c6 <> col4.c6) AND (col2.c6 <> col5.c6) AND (col2.c6 <> col6.c6) AND (col2.c6 <> col7.c6) AND (col2.c6 <> col8.c6) AND (col2.c6 <> col9.c6) AND (col2.c7 <> col3.c7) AND (col2.c7 <> col4.c7) AND (col2.c7 <> col5.c7) AND (col2.c7 <> col6.c7) AND (col2.c7 <> col7.c7) AND (col2.c7 <> col8.c7) AND (col2.c7 <> col9.c7) AND (col2.c8 <> col3.c8) AND (col2.c8 <> col4.c8) AND (col2.c8 <> col5.c8) AND (col2.c8 <> col6.c8) AND (col2.c8 <> col7.c8) AND (col2.c8 <> col8.c8) AND (col2.c8 <> col9.c8) AND (col2.c9 <> col3.c9) AND (col2.c9 <> col4.c9) AND (col2.c9 <> col5.c9) AND (col2.c9 <> col6.c9) AND (col2.c9 <> col7.c9) AND (col2.c9 <> col8.c9) AND (col2.c9 <> col9.c9) AND (col3.c1 <> col4.c1) AND (col3.c1 <> col5.c1) AND (col3.c1 <> col6.c1) AND (col3.c1 <> col7.c1) AND (col3.c1 <> col8.c1) AND (col3.c1 <> col9.c1) AND (col3.c2 <> col4.c2) AND (col3.c2 <> col5.c2) AND (col3.c2 <> col6.c2) AND (col3.c2 <> col7.c2) AND (col3.c2 <> col8.c2) AND (col3.c2 <> col9.c2) AND (col3.c3 <> col4.c3) AND (col3.c3 <> col5.c3) AND (col3.c3 <> col6.c3) AND (col3.c3 <> col7.c3) AND (col3.c3 <> col8.c3) AND (col3.c3 <> col9.c3) AND (col3.c4 <> col4.c4) AND (col3.c4 <> col5.c4) AND (col3.c4 <> col6.c4) AND (col3.c4 <> col7.c4) AND (col3.c4 <> col8.c4) AND (col3.c4 <> col9.c4) AND (col3.c5 <> col4.c5) AND (col3.c5 <> col5.c5) AND (col3.c5 <> col6.c5) AND (col3.c5 <> col7.c5) AND (col3.c5 <> col8.c5) AND (col3.c5 <> col9.c5) AND (col3.c6 <> col4.c6) AND (col3.c6 <> col5.c6) AND (col3.c6 <> col6.c6) AND (col3.c6 <> col7.c6) AND (col3.c6 <> col8.c6) AND (col3.c6 <> col9.c6) AND (col3.c7 <> col4.c7) AND (col3.c7 <> col5.c7) AND (col3.c7 <> col6.c7) AND (col3.c7 <> col7.c7) AND (col3.c7 <> col8.c7) AND (col3.c7 <> col9.c7) AND (col3.c8 <> col4.c8) AND (col3.c8 <> col5.c8) AND (col3.c8 <> col6.c8) AND (col3.c8 <> col7.c8) AND (col3.c8 <> col8.c8) AND (col3.c8 <> col9.c8) AND (col3.c9 <> col4.c9) AND (col3.c9 <> col5.c9) AND (col3.c9 <> col6.c9) AND (col3.c9 <> col7.c9) AND (col3.c9 <> col8.c9) AND (col3.c9 <> col9.c9) AND (col4.c1 <> col5.c1) AND (col4.c1 <> col6.c1) AND (col4.c1 <> col7.c1) AND (col4.c1 <> col8.c1) AND (col4.c1 <> col9.c1) AND (col4.c2 <> col5.c2) AND (col4.c2 <> col6.c2) AND (col4.c2 <> col7.c2) AND (col4.c2 <> col8.c2) AND (col4.c2 <> col9.c2) AND (col4.c3 <> col5.c3) AND (col4.c3 <> col6.c3) AND (col4.c3 <> col7.c3) AND (col4.c3 <> col8.c3) AND (col4.c3 <> col9.c3) AND (col4.c4 <> col5.c4) AND (col4.c4 <> col6.c4) AND (col4.c4 <> col7.c4) AND (col4.c4 <> col8.c4) AND (col4.c4 <> col9.c4) AND (col4.c5 <> col5.c5) AND (col4.c5 <> col6.c5) AND (col4.c5 <> col7.c5) AND (col4.c5 <> col8.c5) AND (col4.c5 <> col9.c5) AND (col4.c6 <> col5.c6) AND (col4.c6 <> col6.c6) AND (col4.c6 <> col7.c6) AND (col4.c6 <> col8.c6) AND (col4.c6 <> col9.c6) AND (col4.c7 <> col5.c7) AND (col4.c7 <> col6.c7) AND (col4.c7 <> col7.c7) AND (col4.c7 <> col8.c7) AND (col4.c7 <> col9.c7) AND (col4.c8 <> col5.c8) AND (col4.c8 <> col6.c8) AND (col4.c8 <> col7.c8) AND (col4.c8 <> col8.c8) AND (col4.c8 <> col9.c8) AND (col4.c9 <> col5.c9) AND (col4.c9 <> col6.c9) AND (col4.c9 <> col7.c9) AND (col4.c9 <> col8.c9) AND (col4.c9 <> col9.c9) AND (col5.c1 <> col6.c1) AND (col5.c1 <> col7.c1) AND (col5.c1 <> col8.c1) AND (col5.c1 <> col9.c1) AND (col5.c2 <> col6.c2) AND (col5.c2 <> col7.c2) AND (col5.c2 <> col8.c2) AND (col5.c2 <> col9.c2) AND (col5.c3 <> col6.c3) AND (col5.c3 <> col7.c3) AND (col5.c3 <> col8.c3) AND (col5.c3 <> col9.c3) AND (col5.c4 <> col6.c4) AND (col5.c4 <> col7.c4) AND (col5.c4 <> col8.c4) AND (col5.c4 <> col9.c4) AND (col5.c5 <> col6.c5) AND (col5.c5 <> col7.c5) AND (col5.c5 <> col8.c5) AND (col5.c5 <> col9.c5) AND (col5.c6 <> col6.c6) AND (col5.c6 <> col7.c6) AND (col5.c6 <> col8.c6) AND (col5.c6 <> col9.c6) AND (col5.c7 <> col6.c7) AND (col5.c7 <> col7.c7) AND (col5.c7 <> col8.c7) AND (col5.c7 <> col9.c7) AND (col5.c8 <> col6.c8) AND (col5.c8 <> col7.c8) AND (col5.c8 <> col8.c8) AND (col5.c8 <> col9.c8) AND (col5.c9 <> col6.c9) AND (col5.c9 <> col7.c9) AND (col5.c9 <> col8.c9) AND (col5.c9 <> col9.c9) AND (col6.c1 <> col7.c1) AND (col6.c1 <> col8.c1) AND (col6.c1 <> col9.c1) AND (col6.c2 <> col7.c2) AND (col6.c2 <> col8.c2) AND (col6.c2 <> col9.c2) AND (col6.c3 <> col7.c3) AND (col6.c3 <> col8.c3) AND (col6.c3 <> col9.c3) AND (col6.c4 <> col7.c4) AND (col6.c4 <> col8.c4) AND (col6.c4 <> col9.c4) AND (col6.c5 <> col7.c5) AND (col6.c5 <> col8.c5) AND (col6.c5 <> col9.c5) AND (col6.c6 <> col7.c6) AND (col6.c6 <> col8.c6) AND (col6.c6 <> col9.c6) AND (col6.c7 <> col7.c7) AND (col6.c7 <> col8.c7) AND (col6.c7 <> col9.c7) AND (col6.c8 <> col7.c8) AND (col6.c8 <> col8.c8) AND (col6.c8 <> col9.c8) AND (col6.c9 <> col7.c9) AND (col6.c9 <> col8.c9) AND (col6.c9 <> col9.c9) AND (col7.c1 <> col8.c1) AND (col7.c1 <> col9.c1) AND (col7.c2 <> col8.c2) AND (col7.c2 <> col9.c2) AND (col7.c3 <> col8.c3) AND (col7.c3 <> col9.c3) AND (col7.c4 <> col8.c4) AND (col7.c4 <> col9.c4) AND (col7.c5 <> col8.c5) AND (col7.c5 <> col9.c5) AND (col7.c6 <> col8.c6) AND (col7.c6 <> col9.c6) AND (col7.c7 <> col8.c7) AND (col7.c7 <> col9.c7) AND (col7.c8 <> col8.c8) AND (col7.c8 <> col9.c8) AND (col7.c9 <> col8.c9) AND (col7.c9 <> col9.c9) AND (col8.c1 <> col9.c1) AND (col8.c2 <> col9.c2) AND (col8.c3 <> col9.c3) AND (col8.c4 <> col9.c4) AND (col8.c5 <> col9.c5) AND (col8.c6 <> col9.c6) AND (col8.c7 <> col9.c7) AND (col8.c8 <> col9.c8) AND (col8.c9 <> col9.c9) AND -- Nombres uniques dans chaque maison de 3x3 (col1.c1 <> col1.c2) AND (col1.c1 <> col1.c3) AND (col1.c1 <> col2.c2) AND (col1.c1 <> col2.c3) AND (col1.c1 <> col3.c2) AND (col1.c1 <> col3.c3) AND (col1.c2 <> col1.c3) AND (col1.c2 <> col2.c1) AND (col1.c2 <> col2.c3) AND (col1.c2 <> col3.c1) AND (col1.c2 <> col3.c3) AND (col1.c3 <> col2.c1) AND (col1.c3 <> col2.c2) AND (col1.c3 <> col3.c1) AND (col1.c3 <> col3.c2) AND (col1.c4 <> col1.c5) AND (col1.c4 <> col1.c6) AND (col1.c4 <> col2.c5) AND (col1.c4 <> col2.c6) AND (col1.c4 <> col3.c5) AND (col1.c4 <> col3.c6) AND (col1.c5 <> col1.c6) AND (col1.c5 <> col2.c4) AND (col1.c5 <> col2.c6) AND (col1.c5 <> col3.c4) AND (col1.c5 <> col3.c6) AND (col1.c6 <> col2.c4) AND (col1.c6 <> col2.c5) AND (col1.c6 <> col3.c4) AND (col1.c6 <> col3.c5) AND (col1.c7 <> col1.c8) AND (col1.c7 <> col1.c9) AND (col1.c7 <> col2.c8) AND (col1.c7 <> col2.c9) AND (col1.c7 <> col3.c8) AND (col1.c7 <> col3.c9) AND (col1.c8 <> col1.c9) AND (col1.c8 <> col2.c7) AND (col1.c8 <> col2.c9) AND (col1.c8 <> col3.c7) AND (col1.c8 <> col3.c9) AND (col1.c9 <> col2.c7) AND (col1.c9 <> col2.c8) AND (col1.c9 <> col3.c7) AND (col1.c9 <> col3.c8) AND (col2.c1 <> col2.c2) AND (col2.c1 <> col2.c3) AND (col2.c1 <> col3.c2) AND (col2.c1 <> col3.c3) AND (col2.c2 <> col2.c3) AND (col2.c2 <> col3.c1) AND (col2.c2 <> col3.c3) AND (col2.c3 <> col3.c1) AND (col2.c3 <> col3.c2) AND (col2.c4 <> col2.c5) AND (col2.c4 <> col2.c6) AND (col2.c4 <> col3.c5) AND (col2.c4 <> col3.c6) AND (col2.c5 <> col2.c6) AND (col2.c5 <> col3.c4) AND (col2.c5 <> col3.c6) AND (col2.c6 <> col3.c4) AND (col2.c6 <> col3.c5) AND (col2.c7 <> col2.c8) AND (col2.c7 <> col2.c9) AND (col2.c7 <> col3.c8) AND (col2.c7 <> col3.c9) AND (col2.c8 <> col2.c9) AND (col2.c8 <> col3.c7) AND (col2.c8 <> col3.c9) AND (col2.c9 <> col3.c7) AND (col2.c9 <> col3.c8) AND (col3.c1 <> col3.c2) AND (col3.c1 <> col3.c3) AND (col3.c2 <> col3.c3) AND (col3.c4 <> col3.c5) AND (col3.c4 <> col3.c6) AND (col3.c5 <> col3.c6) AND (col3.c7 <> col3.c8) AND (col3.c7 <> col3.c9) AND (col3.c8 <> col3.c9) AND (col4.c1 <> col4.c2) AND (col4.c1 <> col4.c3) AND (col4.c1 <> col5.c2) AND (col4.c1 <> col5.c3) AND (col4.c1 <> col6.c2) AND (col4.c1 <> col6.c3) AND (col4.c2 <> col4.c3) AND (col4.c2 <> col5.c1) AND (col4.c2 <> col5.c3) AND (col4.c2 <> col6.c1) AND (col4.c2 <> col6.c3) AND (col4.c3 <> col5.c1) AND (col4.c3 <> col5.c2) AND (col4.c3 <> col6.c1) AND (col4.c3 <> col6.c2) AND (col4.c4 <> col4.c5) AND (col4.c4 <> col4.c6) AND (col4.c4 <> col5.c5) AND (col4.c4 <> col5.c6) AND (col4.c4 <> col6.c5) AND (col4.c4 <> col6.c6) AND (col4.c5 <> col4.c6) AND (col4.c5 <> col5.c4) AND (col4.c5 <> col5.c6) AND (col4.c5 <> col6.c4) AND (col4.c5 <> col6.c6) AND (col4.c6 <> col5.c4) AND (col4.c6 <> col5.c5) AND (col4.c6 <> col6.c4) AND (col4.c6 <> col6.c5) AND (col4.c7 <> col4.c8) AND (col4.c7 <> col4.c9) AND (col4.c7 <> col5.c8) AND (col4.c7 <> col5.c9) AND (col4.c7 <> col6.c8) AND (col4.c7 <> col6.c9) AND (col4.c8 <> col4.c9) AND (col4.c8 <> col5.c7) AND (col4.c8 <> col5.c9) AND (col4.c8 <> col6.c7) AND (col4.c8 <> col6.c9) AND (col4.c9 <> col5.c7) AND (col4.c9 <> col5.c8) AND (col4.c9 <> col6.c7) AND (col4.c9 <> col6.c8) AND (col5.c1 <> col5.c2) AND (col5.c1 <> col5.c3) AND (col5.c1 <> col6.c2) AND (col5.c1 <> col6.c3) AND (col5.c2 <> col5.c3) AND (col5.c2 <> col6.c1) AND (col5.c2 <> col6.c3) AND (col5.c3 <> col6.c1) AND (col5.c3 <> col6.c2) AND (col5.c4 <> col5.c5) AND (col5.c4 <> col5.c6) AND (col5.c4 <> col6.c5) AND (col5.c4 <> col6.c6) AND (col5.c5 <> col5.c6) AND (col5.c5 <> col6.c4) AND (col5.c5 <> col6.c6) AND (col5.c6 <> col6.c4) AND (col5.c6 <> col6.c5) AND (col5.c7 <> col5.c8) AND (col5.c7 <> col5.c9) AND (col5.c7 <> col6.c8) AND (col5.c7 <> col6.c9) AND (col5.c8 <> col5.c9) AND (col5.c8 <> col6.c7) AND (col5.c8 <> col6.c9) AND (col5.c9 <> col6.c7) AND (col5.c9 <> col6.c8) AND (col6.c1 <> col6.c2) AND (col6.c1 <> col6.c3) AND (col6.c2 <> col6.c3) AND (col6.c4 <> col6.c5) AND (col6.c4 <> col6.c6) AND (col6.c5 <> col6.c6) AND (col6.c7 <> col6.c8) AND (col6.c7 <> col6.c9) AND (col6.c8 <> col6.c9) AND (col7.c1 <> col7.c2) AND (col7.c1 <> col7.c3) AND (col7.c1 <> col8.c2) AND (col7.c1 <> col8.c3) AND (col7.c1 <> col9.c2) AND (col7.c1 <> col9.c3) AND (col7.c2 <> col7.c3) AND (col7.c2 <> col8.c1) AND (col7.c2 <> col8.c3) AND (col7.c2 <> col9.c1) AND (col7.c2 <> col9.c3) AND (col7.c3 <> col8.c1) AND (col7.c3 <> col8.c2) AND (col7.c3 <> col9.c1) AND (col7.c3 <> col9.c2) AND (col7.c4 <> col7.c5) AND (col7.c4 <> col7.c6) AND (col7.c4 <> col8.c5) AND (col7.c4 <> col8.c6) AND (col7.c4 <> col9.c5) AND (col7.c4 <> col9.c6) AND (col7.c5 <> col7.c6) AND (col7.c5 <> col8.c4) AND (col7.c5 <> col8.c6) AND (col7.c5 <> col9.c4) AND (col7.c5 <> col9.c6) AND (col7.c6 <> col8.c4) AND (col7.c6 <> col8.c5) AND (col7.c6 <> col9.c4) AND (col7.c6 <> col9.c5) AND (col7.c7 <> col7.c8) AND (col7.c7 <> col7.c9) AND (col7.c7 <> col8.c8) AND (col7.c7 <> col8.c9) AND (col7.c7 <> col9.c8) AND (col7.c7 <> col9.c9) AND (col7.c8 <> col7.c9) AND (col7.c8 <> col8.c7) AND (col7.c8 <> col8.c9) AND (col7.c8 <> col9.c7) AND (col7.c8 <> col9.c9) AND (col7.c9 <> col8.c7) AND (col7.c9 <> col8.c8) AND (col7.c9 <> col9.c7) AND (col7.c9 <> col9.c8) AND (col8.c1 <> col8.c2) AND (col8.c1 <> col8.c3) AND (col8.c1 <> col9.c2) AND (col8.c1 <> col9.c3) AND (col8.c2 <> col8.c3) AND (col8.c2 <> col9.c1) AND (col8.c2 <> col9.c3) AND (col8.c3 <> col9.c1) AND (col8.c3 <> col9.c2) AND (col8.c4 <> col8.c5) AND (col8.c4 <> col8.c6) AND (col8.c4 <> col9.c5) AND (col8.c4 <> col9.c6) AND (col8.c5 <> col8.c6) AND (col8.c5 <> col9.c4) AND (col8.c5 <> col9.c6) AND (col8.c6 <> col9.c4) AND (col8.c6 <> col9.c5) AND (col8.c7 <> col8.c8) AND (col8.c7 <> col8.c9) AND (col8.c7 <> col9.c8) AND (col8.c7 <> col9.c9) AND (col8.c8 <> col8.c9) AND (col8.c8 <> col9.c7) AND (col8.c8 <> col9.c9) AND (col8.c9 <> col9.c7) AND (col8.c9 <> col9.c8) AND (col9.c1 <> col9.c2) AND (col9.c1 <> col9.c3) AND (col9.c2 <> col9.c3) AND (col9.c4 <> col9.c5) AND (col9.c4 <> col9.c6) AND (col9.c5 <> col9.c6) AND (col9.c7 <> col9.c8) AND (col9.c7 <> col9.c9) AND (col9.c8 <> col9.c9);

Finalement, la vue combinée.

USE sudoku; DROP VIEW IF EXISTS sudoku_memory_combined_view; CREATE VIEW sudoku_memory_combined_view AS SELECT t1.* FROM sudoku_memory_rows_view t1 INNER JOIN sudoku_memory_columns_view t2 ON -- Jointures entre représentation-colonnes et représentation-rangées (t1.r1c1 = t2.r1c1) AND (t1.r1c2 = t2.r1c2) AND (t1.r1c3 = t2.r1c3) AND (t1.r1c4 = t2.r1c4) AND (t1.r1c5 = t2.r1c5) AND (t1.r1c6 = t2.r1c6) AND (t1.r1c7 = t2.r1c7) AND (t1.r1c8 = t2.r1c8) AND (t1.r1c9 = t2.r1c9) AND (t1.r2c1 = t2.r2c1) AND (t1.r2c2 = t2.r2c2) AND (t1.r2c3 = t2.r2c3) AND (t1.r2c4 = t2.r2c4) AND (t1.r2c5 = t2.r2c5) AND (t1.r2c6 = t2.r2c6) AND (t1.r2c7 = t2.r2c7) AND (t1.r2c8 = t2.r2c8) AND (t1.r2c9 = t2.r2c9) AND (t1.r3c1 = t2.r3c1) AND (t1.r3c2 = t2.r3c2) AND (t1.r3c3 = t2.r3c3) AND (t1.r3c4 = t2.r3c4) AND (t1.r3c5 = t2.r3c5) AND (t1.r3c6 = t2.r3c6) AND (t1.r3c7 = t2.r3c7) AND (t1.r3c8 = t2.r3c8) AND (t1.r3c9 = t2.r3c9) AND (t1.r4c1 = t2.r4c1) AND (t1.r4c2 = t2.r4c2) AND (t1.r4c3 = t2.r4c3) AND (t1.r4c4 = t2.r4c4) AND (t1.r4c5 = t2.r4c5) AND (t1.r4c6 = t2.r4c6) AND (t1.r4c7 = t2.r4c7) AND (t1.r4c8 = t2.r4c8) AND (t1.r4c9 = t2.r4c9) AND (t1.r5c1 = t2.r5c1) AND (t1.r5c2 = t2.r5c2) AND (t1.r5c3 = t2.r5c3) AND (t1.r5c4 = t2.r5c4) AND (t1.r5c5 = t2.r5c5) AND (t1.r5c6 = t2.r5c6) AND (t1.r5c7 = t2.r5c7) AND (t1.r5c8 = t2.r5c8) AND (t1.r5c9 = t2.r5c9) AND (t1.r6c1 = t2.r6c1) AND (t1.r6c2 = t2.r6c2) AND (t1.r6c3 = t2.r6c3) AND (t1.r6c4 = t2.r6c4) AND (t1.r6c5 = t2.r6c5) AND (t1.r6c6 = t2.r6c6) AND (t1.r6c7 = t2.r6c7) AND (t1.r6c8 = t2.r6c8) AND (t1.r6c9 = t2.r6c9) AND (t1.r7c1 = t2.r7c1) AND (t1.r7c2 = t2.r7c2) AND (t1.r7c3 = t2.r7c3) AND (t1.r7c4 = t2.r7c4) AND (t1.r7c5 = t2.r7c5) AND (t1.r7c6 = t2.r7c6) AND (t1.r7c7 = t2.r7c7) AND (t1.r7c8 = t2.r7c8) AND (t1.r7c9 = t2.r7c9) AND (t1.r8c1 = t2.r8c1) AND (t1.r8c2 = t2.r8c2) AND (t1.r8c3 = t2.r8c3) AND (t1.r8c4 = t2.r8c4) AND (t1.r8c5 = t2.r8c5) AND (t1.r8c6 = t2.r8c6) AND (t1.r8c7 = t2.r8c7) AND (t1.r8c8 = t2.r8c8) AND (t1.r8c9 = t2.r8c9) AND (t1.r9c1 = t2.r9c1) AND (t1.r9c2 = t2.r9c2) AND (t1.r9c3 = t2.r9c3) AND (t1.r9c4 = t2.r9c4) AND (t1.r9c5 = t2.r9c5) AND (t1.r9c6 = t2.r9c6) AND (t1.r9c7 = t2.r9c7) AND (t1.r9c8 = t2.r9c8) AND (t1.r9c9 = t2.r9c9);

Réessayons l’exemple du début de cet article pour comparer :

mysql> SELECT * -> FROM sudoku_memory_combined_view -> WHERE -> (r2c2 = 3) AND (r2c3 = 4) AND (r2c4 = 8) AND (r2c5 = 2) AND -> (r2c6 = 5) AND (r2c7 = 6) AND (r2c8 = 9) AND (r3c2 = 5) AND -> (r3c3 = 9) AND (r3c4 = 3) AND (r3c5 = 6) AND (r3c6 = 4) AND -> (r3c7 = 1) AND (r3c8 = 8) AND (r4c2 = 9) AND (r4c3 = 7) AND -> (r4c4 = 1) AND (r4c5 = 8) AND (r4c6 = 2) AND (r4c7 = 5) AND -> (r4c8 = 6) AND (r6c2 = 8) AND (r6c3 = 1) AND (r6c4 = 4) AND -> (r6c5 = 7) AND (r6c6 = 6) AND (r6c7 = 2) AND (r6c8 = 3) AND -> (r7c2 = 2) AND (r7c3 = 5) AND (r7c4 = 6) AND (r7c5 = 4) AND -> (r7c6 = 1) AND (r7c7 = 9) AND (r7c8 = 7) AND (r8c2 = 7) AND -> (r8c3 = 6) AND (r8c4 = 5) AND (r8c5 = 3) AND (r8c6 = 8) AND -> (r8c7 = 4) AND (r8c8 = 2); +------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+ | r1c1 | r1c2 | r1c3 | r1c4 | r1c5 | r1c6 | r1c7 | r1c8 | r1c9 | r2c1 | r2c2 | r2c3 | r2c4 | r2c5 | r2c6 | r2c7 | r2c8 | r2c9 | r3c1 | r3c2 | r3c3 | r3c4 | r3c5 | r3c6 | r3c7 | r3c8 | r3c9 | r4c1 | r4c2 | r4c3 | r4c4 | r4c5 | r4c6 | r4c7 | r4c8 | r4c9 | r5c1 | r5c2 | r5c3 | r5c4 | r5c5 | r5c6 | r5c7 | r5c8 | r5c9 | r6c1 | r6c2 | r6c3 | r6c4 | r6c5 | r6c6 | r6c7 | r6c8 | r6c9 | r7c1 | r7c2 | r7c3 | r7c4 | r7c5 | r7c6 | r7c7 | r7c8 | r7c9 | r8c1 | r8c2 | r8c3 | r8c4 | r8c5 | r8c6 | r8c7 | r8c8 | r8c9 | r9c1 | r9c2 | r9c3 | r9c4 | r9c5 | r9c6 | r9c7 | r9c8 | r9c9 | +------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+ | 2 | 6 | 8 | 7 | 1 | 9 | 3 | 4 | 5 | 1 | 3 | 4 | 8 | 2 | 5 | 6 | 9 | 7 | 7 | 5 | 9 | 3 | 6 | 4 | 1 | 8 | 2 | 3 | 9 | 7 | 1 | 8 | 2 | 5 | 6 | 4 | 6 | 4 | 2 | 9 | 5 | 3 | 7 | 1 | 8 | 5 | 8 | 1 | 4 | 7 | 6 | 2 | 3 | 9 | 8 | 2 | 5 | 6 | 4 | 1 | 9 | 7 | 3 | 9 | 7 | 6 | 5 | 3 | 8 | 4 | 2 | 1 | 4 | 1 | 3 | 2 | 9 | 7 | 8 | 5 | 6 | +------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+ 1 row in set (0.55 sec)

Wow! Nous sommes passés de 1.5 à 0.55 seconde! Maintenant, qu’en est-il de notre grille à 17 révélés ?

mysql> SELECT * -> FROM sudoku_memory_combined_view -> WHERE -> (r1c8 = 1) AND -> (r2c1 = 4) AND -> (r3c2 = 2) AND -> (r4c5 = 5) AND -> (r4c7 = 4) AND -> (r4c9 = 7) AND -> (r5c3 = 8) AND -> (r5c7 = 3) AND -> (r6c3 = 1) AND -> (r6c5 = 9) AND -> (r7c1 = 3) AND -> (r7c4 = 4) AND -> (r7c7 = 2) AND -> (r8c2 = 5) AND -> (r8c4 = 1) AND -> (r9c4 = 8) AND -> (r9c6 = 6); +------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+ | r1c1 | r1c2 | r1c3 | r1c4 | r1c5 | r1c6 | r1c7 | r1c8 | r1c9 | r2c1 | r2c2 | r2c3 | r2c4 | r2c5 | r2c6 | r2c7 | r2c8 | r2c9 | r3c1 | r3c2 | r3c3 | r3c4 | r3c5 | r3c6 | r3c7 | r3c8 | r3c9 | r4c1 | r4c2 | r4c3 | r4c4 | r4c5 | r4c6 | r4c7 | r4c8 | r4c9 | r5c1 | r5c2 | r5c3 | r5c4 | r5c5 | r5c6 | r5c7 | r5c8 | r5c9 | r6c1 | r6c2 | r6c3 | r6c4 | r6c5 | r6c6 | r6c7 | r6c8 | r6c9 | r7c1 | r7c2 | r7c3 | r7c4 | r7c5 | r7c6 | r7c7 | r7c8 | r7c9 | r8c1 | r8c2 | r8c3 | r8c4 | r8c5 | r8c6 | r8c7 | r8c8 | r8c9 | r9c1 | r9c2 | r9c3 | r9c4 | r9c5 | r9c6 | r9c7 | r9c8 | r9c9 | +------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+ | 6 | 9 | 3 | 7 | 8 | 4 | 5 | 1 | 2 | 4 | 8 | 7 | 5 | 1 | 2 | 9 | 3 | 6 | 1 | 2 | 5 | 9 | 6 | 3 | 8 | 7 | 4 | 9 | 3 | 2 | 6 | 5 | 1 | 4 | 8 | 7 | 5 | 6 | 8 | 2 | 4 | 7 | 3 | 9 | 1 | 7 | 4 | 1 | 3 | 9 | 8 | 6 | 2 | 5 | 3 | 1 | 9 | 4 | 7 | 5 | 2 | 6 | 8 | 8 | 5 | 6 | 1 | 2 | 9 | 7 | 4 | 3 | 2 | 7 | 4 | 8 | 3 | 6 | 1 | 5 | 9 | +------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+ 1 row in set (7.41 sec)

Fantastique! Nous sommes passés de 20 minutes à 7 secondes! Mais il y a encore place à amélioration!

**5. Presser encore plus fort
**

Maintenant que nous sommes en mesure d’obtenir des résultats dans des temps raisonnables en utilisant une table de type MEMORY, nous pouvons regarder du côté des variables système pour essayer de les optimiser.

Mais avant de se lancer dans cette entreprise, il importe d’avoir un jeu d’essai afin d’effectuer des tests **reproduisibles** et **mesurables** pour vérifier l’impact de chacun des changements sur ces variables.

Nous allons tout d’abord créer une table qui nous permettra de sauvegarder le temps d’exécution de toutes les grilles de notre jeu d’essai.

DROP TABLE IF EXISTS tests; CREATE TABLE tests ( debut DATETIME, fin DATETIME ) ENGINE=MYISAM;

Maintenant, nous allons créer notre jeu d’essai. Évidemment notre échantillon de grilles est varié de façon à être représentatif afin de mesurer chaque option de façon précise.

USE sudoku; TRUNCATE tests; INSERT INTO tests(debut, fin) VALUES (NOW(), NULL); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 1) AND (r1c3 = 3) AND (r1c4 = 7) AND (r1c9 = 5) AND (r2c4 = 6) AND (r2c6 = 4) AND (r3c1 = 8) AND (r4c4 = 8) AND (r4c5 = 1) AND (r5c2 = 9) AND (r5c7 = 7) AND (r6c2 = 6) AND (r6c8 = 9) AND (r7c2 = 2) AND (r7c7 = 4) AND (r8c1 = 5) AND (r8c5 = 3) AND (r9c8 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 8) AND (r1c4 = 3) AND (r1c6 = 7) AND (r2c3 = 9) AND (r3c1 = 2) AND (r3c2 = 7) AND (r3c5 = 4) AND (r4c2 = 3) AND (r4c5 = 1) AND (r5c1 = 4) AND (r5c4 = 9) AND (r5c7 = 2) AND (r5c8 = 8) AND (r6c4 = 6) AND (r6c6 = 2) AND (r6c7 = 4) AND (r6c8 = 3) AND (r7c1 = 3) AND (r7c2 = 1) AND (r7c6 = 6) AND (r8c1 = 6) AND (r8c3 = 8) AND (r8c4 = 1) AND (r8c9 = 7) AND (r9c5 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 2) AND (r1c8 = 1) AND (r2c6 = 2) AND (r2c8 = 3) AND (r2c9 = 4) AND (r3c3 = 3) AND (r3c5 = 5) AND (r4c4 = 4) AND (r4c8 = 6) AND (r5c3 = 2) AND (r5c7 = 9) AND (r6c2 = 5) AND (r6c6 = 8) AND (r7c5 = 3) AND (r7c7 = 5) AND (r8c1 = 7) AND (r8c2 = 9) AND (r8c4 = 1) AND (r9c2 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r2c2 = 8) AND (r3c5 = 5) AND (r3c6 = 3) AND (r3c8 = 8) AND (r3c9 = 9) AND (r4c2 = 2) AND (r4c3 = 4) AND (r4c6 = 9) AND (r5c5 = 1) AND (r5c9 = 5) AND (r6c2 = 1) AND (r6c6 = 7) AND (r7c3 = 2) AND (r7c4 = 1) AND (r7c7 = 3) AND (r8c1 = 9) AND (r8c6 = 5) AND (r8c9 = 7) AND (r9c1 = 5) AND (r9c5 = 8) AND (r9c8 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 5) AND (r1c6 = 8) AND (r1c7 = 6) AND (r2c6 = 6) AND (r2c7 = 2) AND (r2c8 = 7) AND (r3c2 = 1) AND (r4c1 = 9) AND (r4c4 = 7) AND (r4c5 = 6) AND (r4c6 = 2) AND (r5c1 = 7) AND (r6c3 = 8) AND (r7c1 = 2) AND (r7c3 = 3) AND (r7c7 = 8) AND (r8c4 = 1) AND (r8c5 = 9) AND (r8c9 = 5) AND (r9c3 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 5) AND (r1c4 = 8) AND (r1c5 = 3) AND (r2c7 = 7) AND (r2c8 = 1) AND (r3c2 = 3) AND (r4c1 = 7) AND (r4c4 = 4) AND (r4c7 = 8) AND (r5c1 = 1) AND (r5c3 = 2) AND (r7c2 = 8) AND (r7c4 = 6) AND (r7c7 = 4) AND (r8c1 = 9) AND (r8c6 = 2) AND (r9c5 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 7) AND (r1c9 = 5) AND (r2c2 = 3) AND (r2c8 = 7) AND (r3c1 = 2) AND (r3c3 = 5) AND (r3c8 = 3) AND (r3c9 = 8) AND (r4c8 = 8) AND (r4c9 = 9) AND (r5c1 = 5) AND (r5c3 = 8) AND (r5c4 = 2) AND (r5c6 = 9) AND (r5c7 = 7) AND (r5c9 = 4) AND (r6c1 = 3) AND (r7c1 = 6) AND (r7c3 = 4) AND (r7c4 = 9) AND (r7c5 = 8) AND (r7c6 = 7) AND (r7c7 = 5) AND (r8c1 = 9) AND (r8c4 = 5) AND (r9c4 = 4) AND (r9c6 = 6) AND (r9c9 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 4) AND (r1c2 = 6) AND (r1c3 = 8) AND (r1c7 = 1) AND (r2c2 = 7) AND (r2c4 = 4) AND (r2c6 = 8) AND (r2c8 = 5) AND (r3c4 = 6) AND (r4c3 = 6) AND (r4c4 = 1) AND (r4c5 = 8) AND (r4c6 = 3) AND (r4c9 = 7) AND (r5c3 = 7) AND (r6c1 = 3) AND (r6c5 = 5) AND (r6c7 = 2) AND (r6c9 = 1) AND (r7c6 = 7) AND (r8c4 = 8) AND (r8c6 = 2) AND (r8c7 = 5) AND (r9c6 = 5) AND (r9c7 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 9) AND (r1c8 = 1) AND (r2c6 = 2) AND (r2c8 = 3) AND (r2c9 = 4) AND (r3c3 = 5) AND (r3c5 = 6) AND (r4c4 = 3) AND (r4c8 = 7) AND (r5c3 = 2) AND (r5c7 = 6) AND (r6c2 = 1) AND (r6c6 = 5) AND (r7c5 = 8) AND (r7c7 = 2) AND (r8c1 = 7) AND (r8c2 = 3) AND (r8c4 = 9) AND (r9c2 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c6 = 7) AND (r1c9 = 2) AND (r2c5 = 4) AND (r2c6 = 5) AND (r2c8 = 7) AND (r3c3 = 9) AND (r4c1 = 3) AND (r4c5 = 5) AND (r4c7 = 8) AND (r5c1 = 4) AND (r5c2 = 8) AND (r5c4 = 9) AND (r5c6 = 1) AND (r5c9 = 7) AND (r6c3 = 7) AND (r6c6 = 4) AND (r6c7 = 2) AND (r6c9 = 9) AND (r7c5 = 1) AND (r7c7 = 3) AND (r8c8 = 5) AND (r9c2 = 3) AND (r9c4 = 8) AND (r9c5 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 9) AND (r1c8 = 7) AND (r2c8 = 2) AND (r2c9 = 4) AND (r3c1 = 1) AND (r4c2 = 2) AND (r4c3 = 9) AND (r4c9 = 5) AND (r5c6 = 1) AND (r5c7 = 6) AND (r6c2 = 4) AND (r6c5 = 8) AND (r7c4 = 4) AND (r7c5 = 3) AND (r8c1 = 5) AND (r8c7 = 8) AND (r9c4 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r2c2 = 9) AND (r2c3 = 3) AND (r3c2 = 7) AND (r3c8 = 3) AND (r4c3 = 9) AND (r4c5 = 6) AND (r4c8 = 7) AND (r4c9 = 4) AND (r5c3 = 6) AND (r5c5 = 7) AND (r5c7 = 3) AND (r5c8 = 9) AND (r6c2 = 3) AND (r6c4 = 5) AND (r6c7 = 6) AND (r6c8 = 8) AND (r7c1 = 9) AND (r7c5 = 8) AND (r7c6 = 2) AND (r7c7 = 4) AND (r8c2 = 8) AND (r8c3 = 2) AND (r8c5 = 3) AND (r8c8 = 5) AND (r8c9 = 7) AND (r9c2 = 6) AND (r9c3 = 4) AND (r9c4 = 7) AND (r9c5 = 5) AND (r9c8 = 2) AND (r9c9 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 7) AND (r1c5 = 5) AND (r1c8 = 6) AND (r1c9 = 9) AND (r2c1 = 6) AND (r2c8 = 4) AND (r3c2 = 1) AND (r3c5 = 8) AND (r3c6 = 9) AND (r3c9 = 3) AND (r4c4 = 1) AND (r5c4 = 3) AND (r6c2 = 8) AND (r6c8 = 9) AND (r7c1 = 4) AND (r7c2 = 6) AND (r8c3 = 7) AND (r8c6 = 3) AND (r8c9 = 8) AND (r9c2 = 5) AND (r9c3 = 8) AND (r9c4 = 7) AND (r9c6 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 7) AND (r1c5 = 9) AND (r1c6 = 4) AND (r2c2 = 1) AND (r2c6 = 7) AND (r3c3 = 9) AND (r3c4 = 2) AND (r3c5 = 1) AND (r4c1 = 2) AND (r4c4 = 5) AND (r4c6 = 9) AND (r5c3 = 8) AND (r5c4 = 6) AND (r6c1 = 9) AND (r6c2 = 5) AND (r6c6 = 1) AND (r6c8 = 2) AND (r6c9 = 7) AND (r7c1 = 8) AND (r7c6 = 2) AND (r7c7 = 6) AND (r8c1 = 1) AND (r8c5 = 5) AND (r8c6 = 8) AND (r8c9 = 2) AND (r9c4 = 7) AND (r9c5 = 4) AND (r9c9 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 1) AND (r1c4 = 6) AND (r1c5 = 2) AND (r2c1 = 5) AND (r2c8 = 4) AND (r2c9 = 3) AND (r3c5 = 9) AND (r4c1 = 7) AND (r4c8 = 8) AND (r5c3 = 5) AND (r5c9 = 4) AND (r6c4 = 1) AND (r7c6 = 3) AND (r7c7 = 6) AND (r8c2 = 9) AND (r8c7 = 2) AND (r9c1 = 8) AND (r9c6 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 5) AND (r1c3 = 8) AND (r1c6 = 6) AND (r1c7 = 3) AND (r1c8 = 2) AND (r1c9 = 4) AND (r2c1 = 9) AND (r2c2 = 2) AND (r2c3 = 3) AND (r2c6 = 8) AND (r2c7 = 5) AND (r2c8 = 6) AND (r3c5 = 5) AND (r4c9 = 8) AND (r5c2 = 8) AND (r5c3 = 7) AND (r5c6 = 9) AND (r7c2 = 4) AND (r7c4 = 6) AND (r7c6 = 7) AND (r7c8 = 5) AND (r8c1 = 3) AND (r8c5 = 9) AND (r8c6 = 5) AND (r8c8 = 8) AND (r8c9 = 2) AND (r9c2 = 9) AND (r9c3 = 5) AND (r9c5 = 8) AND (r9c7 = 6) AND (r9c8 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 3) AND (r1c5 = 7) AND (r1c7 = 8) AND (r2c4 = 4) AND (r2c6 = 3) AND (r3c1 = 2) AND (r3c4 = 5) AND (r3c5 = 6) AND (r3c6 = 8) AND (r3c9 = 3) AND (r4c2 = 6) AND (r4c3 = 2) AND (r4c7 = 5) AND (r4c8 = 3) AND (r5c1 = 1) AND (r5c3 = 5) AND (r5c7 = 9) AND (r5c9 = 4) AND (r6c2 = 3) AND (r6c3 = 9) AND (r6c7 = 2) AND (r6c8 = 1) AND (r7c1 = 3) AND (r7c4 = 6) AND (r7c5 = 2) AND (r7c6 = 7) AND (r7c9 = 5) AND (r8c4 = 9) AND (r8c6 = 5) AND (r9c3 = 7) AND (r9c5 = 8) AND (r9c7 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 3) AND (r1c3 = 8) AND (r2c1 = 7) AND (r2c6 = 8) AND (r3c1 = 6) AND (r3c2 = 4) AND (r3c3 = 9) AND (r3c4 = 3) AND (r3c5 = 1) AND (r3c6 = 7) AND (r3c8 = 2) AND (r4c1 = 1) AND (r4c2 = 7) AND (r4c5 = 3) AND (r4c6 = 6) AND (r4c8 = 8) AND (r4c9 = 2) AND (r5c1 = 3) AND (r5c3 = 6) AND (r5c4 = 2) AND (r5c6 = 1) AND (r5c8 = 7) AND (r5c9 = 9) AND (r6c5 = 7) AND (r7c1 = 4) AND (r7c2 = 9) AND (r7c8 = 1) AND (r8c2 = 6) AND (r8c3 = 1) AND (r8c5 = 9) AND (r8c8 = 3); SELECT * FROM sudoku_memory_combined_view WHERE (r1c6 = 5) AND (r1c8 = 8) AND (r2c2 = 1) AND (r2c6 = 3) AND (r3c1 = 3) AND (r3c3 = 7) AND (r3c4 = 6) AND (r4c2 = 9) AND (r4c4 = 1) AND (r4c5 = 7) AND (r4c6 = 6) AND (r4c7 = 3) AND (r5c4 = 9) AND (r5c6 = 8) AND (r5c8 = 1) AND (r6c1 = 2) AND (r7c2 = 6) AND (r8c2 = 8) AND (r8c6 = 1) AND (r8c8 = 6) AND (r9c2 = 3) AND (r9c4 = 2) AND (r9c9 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 8) AND (r1c7 = 4) AND (r1c9 = 3) AND (r2c1 = 9) AND (r2c4 = 3) AND (r2c7 = 7) AND (r3c2 = 1) AND (r3c3 = 5) AND (r3c6 = 2) AND (r4c1 = 6) AND (r4c8 = 9) AND (r4c9 = 5) AND (r5c2 = 3) AND (r5c3 = 7) AND (r6c4 = 8) AND (r7c7 = 8) AND (r7c8 = 3) AND (r7c9 = 2) AND (r8c2 = 2) AND (r8c5 = 9) AND (r9c1 = 8) AND (r9c4 = 7) AND (r9c9 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 7) AND (r1c4 = 2) AND (r1c6 = 4) AND (r1c8 = 5) AND (r2c2 = 4) AND (r2c9 = 2) AND (r3c2 = 2) AND (r3c5 = 8) AND (r3c9 = 6) AND (r4c3 = 7) AND (r4c9 = 5) AND (r5c1 = 8) AND (r5c4 = 5) AND (r6c1 = 6) AND (r6c3 = 3) AND (r6c8 = 7) AND (r7c3 = 9) AND (r7c4 = 7) AND (r8c1 = 3) AND (r8c3 = 2) AND (r8c5 = 5) AND (r8c8 = 6) AND (r9c3 = 5) AND (r9c4 = 3) AND (r9c7 = 9) AND (r9c8 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c7 = 8) AND (r1c8 = 7) AND (r2c1 = 2) AND (r2c2 = 6) AND (r3c2 = 4) AND (r3c5 = 6) AND (r3c6 = 5) AND (r4c3 = 7) AND (r5c6 = 2) AND (r5c8 = 3) AND (r6c6 = 3) AND (r6c8 = 4) AND (r6c9 = 5) AND (r7c4 = 3) AND (r8c3 = 2) AND (r8c4 = 8) AND (r8c5 = 9) AND (r8c6 = 7) AND (r9c2 = 5) AND (r9c9 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 3) AND (r1c5 = 8) AND (r1c8 = 7) AND (r1c9 = 1) AND (r2c2 = 6) AND (r2c3 = 7) AND (r3c1 = 8) AND (r5c1 = 7) AND (r5c2 = 2) AND (r5c3 = 9) AND (r5c5 = 3) AND (r5c6 = 1) AND (r5c8 = 6) AND (r5c9 = 4) AND (r6c1 = 3) AND (r6c2 = 8) AND (r6c3 = 1) AND (r7c3 = 8) AND (r7c5 = 1) AND (r7c7 = 7) AND (r7c8 = 4) AND (r8c2 = 1) AND (r8c3 = 2) AND (r8c4 = 6) AND (r8c8 = 8) AND (r8c9 = 3) AND (r9c1 = 6) AND (r9c4 = 3) AND (r9c5 = 4) AND (r9c8 = 1) AND (r9c9 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c8 = 4) AND (r2c5 = 8) AND (r2c9 = 7) AND (r3c4 = 1) AND (r3c5 = 4) AND (r3c6 = 6) AND (r3c7 = 9) AND (r3c9 = 8) AND (r4c1 = 2) AND (r4c5 = 6) AND (r4c9 = 3) AND (r5c3 = 1) AND (r5c5 = 9) AND (r5c9 = 6) AND (r6c2 = 8) AND (r6c3 = 6) AND (r6c4 = 3) AND (r6c5 = 7) AND (r6c7 = 4) AND (r7c5 = 1) AND (r7c7 = 7) AND (r8c1 = 9) AND (r8c2 = 4) AND (r8c8 = 3) AND (r8c9 = 1) AND (r9c6 = 7) AND (r9c9 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 3) AND (r1c5 = 2) AND (r1c6 = 6) AND (r2c7 = 4) AND (r2c9 = 1) AND (r3c1 = 5) AND (r4c1 = 2) AND (r4c8 = 6) AND (r5c6 = 5) AND (r5c8 = 3) AND (r6c2 = 4) AND (r6c4 = 1) AND (r7c4 = 4) AND (r7c5 = 1) AND (r7c7 = 7) AND (r8c4 = 8) AND (r9c1 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 4) AND (r1c7 = 8) AND (r1c8 = 1) AND (r2c1 = 9) AND (r2c4 = 6) AND (r2c6 = 7) AND (r3c3 = 8) AND (r3c6 = 2) AND (r3c8 = 6) AND (r4c6 = 1) AND (r4c8 = 4) AND (r4c9 = 2) AND (r5c2 = 3) AND (r6c1 = 6) AND (r6c2 = 4) AND (r7c1 = 8) AND (r7c2 = 1) AND (r8c7 = 4) AND (r8c8 = 3) AND (r9c3 = 7) AND (r9c4 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 3) AND (r1c3 = 4) AND (r1c6 = 5) AND (r1c8 = 8) AND (r2c2 = 5) AND (r2c5 = 9) AND (r2c8 = 4) AND (r2c9 = 3) AND (r3c1 = 9) AND (r3c2 = 8) AND (r3c4 = 2) AND (r3c9 = 5) AND (r4c1 = 3) AND (r4c5 = 7) AND (r4c9 = 8) AND (r5c2 = 4) AND (r5c6 = 3) AND (r5c7 = 6) AND (r5c8 = 9) AND (r6c2 = 9) AND (r6c5 = 6) AND (r6c7 = 2) AND (r7c1 = 6) AND (r7c5 = 5) AND (r7c6 = 7) AND (r8c5 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 2) AND (r1c5 = 5) AND (r1c6 = 4) AND (r1c7 = 3) AND (r1c8 = 6) AND (r1c9 = 1) AND (r2c4 = 2) AND (r3c5 = 1) AND (r3c6 = 9) AND (r4c4 = 4) AND (r4c6 = 8) AND (r5c2 = 4) AND (r5c4 = 3) AND (r5c5 = 2) AND (r5c6 = 5) AND (r5c7 = 1) AND (r5c8 = 8) AND (r6c5 = 6) AND (r6c8 = 9) AND (r6c9 = 4) AND (r7c1 = 3) AND (r7c4 = 1) AND (r7c6 = 2) AND (r7c9 = 5) AND (r8c9 = 3) AND (r9c6 = 6) AND (r9c7 = 2) AND (r9c8 = 1) AND (r9c9 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 1) AND (r1c5 = 6) AND (r2c2 = 3) AND (r2c7 = 5) AND (r2c9 = 4) AND (r3c5 = 2) AND (r4c8 = 7) AND (r4c9 = 2) AND (r5c3 = 1) AND (r5c4 = 5) AND (r5c5 = 7) AND (r5c7 = 9) AND (r6c2 = 4) AND (r6c8 = 1) AND (r7c2 = 9) AND (r7c3 = 2) AND (r8c4 = 7) AND (r8c7 = 6) AND (r8c8 = 3) AND (r9c8 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 8) AND (r1c3 = 5) AND (r1c9 = 2) AND (r2c4 = 9) AND (r2c6 = 1) AND (r3c1 = 3) AND (r4c2 = 6) AND (r4c4 = 7) AND (r4c7 = 4) AND (r5c1 = 2) AND (r5c5 = 5) AND (r6c8 = 6) AND (r7c4 = 3) AND (r7c5 = 8) AND (r8c2 = 1) AND (r8c7 = 7) AND (r9c2 = 4) AND (r9c8 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r2c2 = 7) AND (r2c7 = 8) AND (r2c9 = 4) AND (r3c5 = 9) AND (r3c6 = 8) AND (r3c7 = 3) AND (r3c9 = 2) AND (r4c1 = 6) AND (r4c4 = 1) AND (r4c7 = 9) AND (r5c3 = 7) AND (r5c8 = 3) AND (r6c1 = 2) AND (r6c2 = 8) AND (r6c6 = 3) AND (r6c7 = 6) AND (r7c2 = 3) AND (r7c4 = 9) AND (r7c5 = 4) AND (r7c6 = 6) AND (r7c9 = 8) AND (r8c2 = 2) AND (r9c1 = 1) AND (r9c3 = 4) AND (r9c4 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 6) AND (r1c8 = 1) AND (r2c6 = 2) AND (r2c8 = 3) AND (r2c9 = 4) AND (r3c3 = 2) AND (r3c5 = 5) AND (r4c4 = 6) AND (r4c8 = 7) AND (r5c3 = 8) AND (r5c7 = 9) AND (r6c2 = 5) AND (r6c6 = 3) AND (r7c5 = 6) AND (r7c7 = 5) AND (r8c1 = 7) AND (r8c2 = 1) AND (r8c4 = 9) AND (r9c2 = 3); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 8) AND (r1c3 = 3) AND (r1c7 = 6) AND (r1c8 = 4) AND (r2c1 = 1) AND (r2c2 = 2) AND (r2c5 = 6) AND (r2c7 = 5) AND (r3c1 = 5) AND (r3c4 = 8) AND (r3c5 = 9) AND (r3c6 = 3) AND (r3c8 = 2) AND (r3c9 = 1) AND (r4c5 = 3) AND (r5c2 = 6) AND (r5c5 = 2) AND (r5c6 = 5) AND (r5c8 = 1) AND (r5c9 = 3) AND (r6c2 = 1) AND (r6c6 = 9) AND (r6c8 = 5) AND (r7c1 = 4) AND (r7c4 = 3) AND (r7c6 = 1) AND (r8c2 = 5) AND (r9c4 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 5) AND (r1c3 = 3) AND (r1c5 = 9) AND (r2c7 = 8) AND (r2c9 = 1) AND (r3c1 = 2) AND (r4c1 = 4) AND (r4c5 = 2) AND (r4c8 = 5) AND (r5c2 = 1) AND (r5c4 = 8) AND (r6c2 = 6) AND (r6c4 = 7) AND (r7c4 = 4) AND (r7c6 = 7) AND (r7c7 = 6) AND (r8c8 = 3) AND (r9c1 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 1) AND (r1c4 = 7) AND (r1c7 = 2) AND (r1c9 = 5) AND (r2c8 = 6) AND (r2c9 = 3) AND (r3c3 = 3) AND (r3c5 = 6) AND (r4c1 = 5) AND (r4c4 = 3) AND (r4c9 = 7) AND (r6c3 = 8) AND (r6c4 = 2) AND (r6c6 = 7) AND (r6c7 = 3) AND (r6c8 = 9) AND (r7c8 = 7) AND (r8c1 = 2) AND (r8c4 = 5) AND (r8c7 = 1) AND (r9c2 = 6) AND (r9c4 = 8) AND (r9c5 = 3) AND (r9c6 = 1) AND (r9c7 = 5) AND (r9c9 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 9) AND (r1c4 = 5) AND (r1c6 = 6) AND (r1c7 = 4) AND (r1c8 = 2) AND (r2c1 = 2) AND (r2c2 = 3) AND (r2c7 = 8) AND (r2c9 = 5) AND (r3c2 = 5) AND (r3c3 = 4) AND (r3c5 = 3) AND (r3c8 = 6) AND (r3c9 = 9) AND (r4c3 = 8) AND (r4c4 = 6) AND (r4c5 = 7) AND (r4c6 = 5) AND (r6c4 = 3) AND (r6c5 = 2) AND (r6c6 = 9) AND (r6c9 = 6) AND (r7c2 = 4) AND (r7c3 = 2) AND (r7c5 = 9) AND (r7c6 = 3) AND (r7c7 = 6) AND (r8c4 = 4) AND (r8c5 = 6) AND (r9c1 = 3) AND (r9c4 = 2) AND (r9c6 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 3) AND (r1c5 = 5) AND (r2c3 = 9) AND (r2c7 = 1) AND (r3c6 = 9) AND (r3c9 = 6) AND (r4c4 = 8) AND (r4c9 = 5) AND (r5c5 = 1) AND (r5c7 = 8) AND (r5c8 = 3) AND (r6c2 = 3) AND (r6c3 = 2) AND (r6c8 = 7) AND (r7c1 = 1) AND (r7c2 = 8) AND (r7c7 = 3) AND (r8c3 = 7) AND (r8c8 = 2) AND (r9c2 = 5) AND (r9c7 = 7) AND (r9c9 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 6) AND (r1c7 = 8) AND (r1c9 = 7) AND (r2c3 = 3) AND (r2c8 = 4) AND (r3c1 = 2) AND (r3c2 = 9) AND (r3c5 = 7) AND (r3c9 = 6) AND (r4c4 = 9) AND (r4c7 = 2) AND (r4c9 = 3) AND (r5c4 = 2) AND (r5c5 = 6) AND (r5c9 = 9) AND (r7c1 = 3) AND (r7c2 = 8) AND (r7c5 = 2) AND (r8c3 = 7) AND (r8c7 = 1) AND (r8c9 = 4) AND (r9c4 = 1) AND (r9c8 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 4) AND (r1c8 = 1) AND (r2c6 = 1) AND (r2c8 = 2) AND (r2c9 = 3) AND (r3c5 = 5) AND (r4c4 = 6) AND (r4c8 = 4) AND (r5c3 = 3) AND (r5c7 = 5) AND (r6c2 = 7) AND (r6c6 = 2) AND (r7c5 = 4) AND (r7c7 = 8) AND (r8c1 = 2) AND (r8c2 = 1) AND (r8c4 = 8) AND (r8c8 = 7) AND (r9c2 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 5) AND (r1c5 = 7) AND (r1c7 = 4) AND (r1c8 = 1) AND (r2c3 = 7) AND (r2c4 = 2) AND (r2c7 = 3) AND (r2c9 = 9) AND (r3c5 = 4) AND (r3c7 = 7) AND (r3c9 = 2) AND (r4c3 = 8) AND (r4c6 = 2) AND (r5c4 = 3) AND (r5c5 = 9) AND (r5c7 = 2) AND (r5c8 = 4) AND (r6c2 = 3) AND (r6c4 = 4) AND (r6c9 = 5) AND (r7c4 = 9) AND (r7c5 = 2) AND (r7c7 = 5) AND (r8c4 = 8) AND (r8c5 = 1) AND (r8c6 = 4) AND (r8c9 = 7) AND (r9c1 = 8) AND (r9c6 = 5); SELECT * FROM sudoku_memory_combined_view WHERE (r2c2 = 7) AND (r2c4 = 6) AND (r2c5 = 3) AND (r3c3 = 9) AND (r3c4 = 8) AND (r3c8 = 6) AND (r4c7 = 7) AND (r4c8 = 3) AND (r5c3 = 2) AND (r5c4 = 3) AND (r5c7 = 5) AND (r5c9 = 9) AND (r6c3 = 6) AND (r6c5 = 1) AND (r6c7 = 2) AND (r7c1 = 2) AND (r7c3 = 3) AND (r7c6 = 1) AND (r8c1 = 9) AND (r8c5 = 6) AND (r8c9 = 8) AND (r9c2 = 8) AND (r9c3 = 1) AND (r9c4 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 9) AND (r2c4 = 3) AND (r2c5 = 6) AND (r2c7 = 1) AND (r3c5 = 1) AND (r3c6 = 9) AND (r3c7 = 5) AND (r4c1 = 5) AND (r4c8 = 9) AND (r4c9 = 2) AND (r5c5 = 7) AND (r6c4 = 6) AND (r6c9 = 3) AND (r7c4 = 9) AND (r7c7 = 7) AND (r7c8 = 5) AND (r8c5 = 5) AND (r8c6 = 1) AND (r8c8 = 2) AND (r9c2 = 6) AND (r9c5 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 3) AND (r1c3 = 7) AND (r2c1 = 9) AND (r2c2 = 4) AND (r2c3 = 6) AND (r2c9 = 3) AND (r3c1 = 1) AND (r3c4 = 7) AND (r4c1 = 2) AND (r4c2 = 8) AND (r4c3 = 1) AND (r4c4 = 4) AND (r5c3 = 3) AND (r5c6 = 6) AND (r6c1 = 4) AND (r7c5 = 1) AND (r7c7 = 9) AND (r7c9 = 2) AND (r8c3 = 2) AND (r8c4 = 9) AND (r8c6 = 4) AND (r8c9 = 6) AND (r9c1 = 3) AND (r9c2 = 1) AND (r9c5 = 8) AND (r9c8 = 4) AND (r9c9 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r2c1 = 4) AND (r2c2 = 2) AND (r2c3 = 9) AND (r2c5 = 8) AND (r2c6 = 3) AND (r3c2 = 8) AND (r3c4 = 5) AND (r3c6 = 4) AND (r4c5 = 2) AND (r4c7 = 4) AND (r4c8 = 7) AND (r5c2 = 4) AND (r5c4 = 8) AND (r5c6 = 9) AND (r5c8 = 5) AND (r6c3 = 2) AND (r6c4 = 1) AND (r6c7 = 3) AND (r6c9 = 8) AND (r7c2 = 9) AND (r8c1 = 8) AND (r8c5 = 7) AND (r8c6 = 2) AND (r8c9 = 4) AND (r9c4 = 9) AND (r9c5 = 1) AND (r9c6 = 8) AND (r9c9 = 3); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 2) AND (r1c7 = 4) AND (r1c9 = 9) AND (r2c2 = 4) AND (r2c8 = 5) AND (r2c9 = 2) AND (r3c3 = 5) AND (r3c7 = 8) AND (r3c8 = 7) AND (r4c2 = 8) AND (r4c8 = 9) AND (r4c9 = 6) AND (r5c3 = 7) AND (r5c6 = 9) AND (r5c7 = 2) AND (r5c8 = 3) AND (r6c3 = 2) AND (r6c5 = 3) AND (r6c7 = 7) AND (r6c9 = 8) AND (r7c2 = 5) AND (r7c5 = 8) AND (r7c7 = 9) AND (r8c1 = 2) AND (r8c3 = 6) AND (r9c3 = 8) AND (r9c4 = 5) AND (r9c6 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 9) AND (r1c5 = 6) AND (r2c3 = 2) AND (r2c7 = 6) AND (r3c2 = 1) AND (r3c6 = 9) AND (r3c7 = 5) AND (r3c9 = 3) AND (r4c2 = 7) AND (r4c7 = 8) AND (r5c1 = 1) AND (r5c8 = 3) AND (r6c3 = 9) AND (r6c9 = 5) AND (r7c2 = 8) AND (r7c6 = 3) AND (r7c9 = 9) AND (r8c1 = 7) AND (r8c3 = 5) AND (r8c6 = 2) AND (r8c7 = 1) AND (r8c9 = 6) AND (r9c1 = 6) AND (r9c8 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c7 = 3) AND (r1c8 = 1) AND (r2c1 = 7) AND (r2c4 = 5) AND (r3c1 = 2) AND (r3c5 = 4) AND (r4c2 = 3) AND (r4c3 = 9) AND (r4c6 = 8) AND (r5c8 = 6) AND (r5c9 = 2) AND (r6c2 = 1) AND (r7c1 = 5) AND (r7c4 = 6) AND (r7c9 = 7) AND (r8c2 = 8) AND (r8c7 = 9) AND (r9c5 = 5); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 5) AND (r1c3 = 1) AND (r1c5 = 7) AND (r1c8 = 6) AND (r1c9 = 3) AND (r2c2 = 6) AND (r2c8 = 2) AND (r3c2 = 2) AND (r3c3 = 3) AND (r3c5 = 6) AND (r3c7 = 7) AND (r3c8 = 9) AND (r5c2 = 1) AND (r5c7 = 3) AND (r5c8 = 5) AND (r6c3 = 9) AND (r6c8 = 4) AND (r7c1 = 6) AND (r7c4 = 4) AND (r7c6 = 9) AND (r7c7 = 5) AND (r8c1 = 5) AND (r8c2 = 9) AND (r8c4 = 6) AND (r8c5 = 3) AND (r8c8 = 7) AND (r8c9 = 4) AND (r9c3 = 4) AND (r9c4 = 7) AND (r9c5 = 5) AND (r9c8 = 3) AND (r9c9 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 7) AND (r1c8 = 9) AND (r2c6 = 2) AND (r2c8 = 3) AND (r2c9 = 4) AND (r3c3 = 2) AND (r3c5 = 5) AND (r4c4 = 4) AND (r4c8 = 2) AND (r5c3 = 6) AND (r5c7 = 7) AND (r6c2 = 5) AND (r6c6 = 3) AND (r7c5 = 6) AND (r7c7 = 5) AND (r8c1 = 8) AND (r8c2 = 1) AND (r8c4 = 9) AND (r9c2 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 1) AND (r1c8 = 8) AND (r2c6 = 1) AND (r2c8 = 2) AND (r2c9 = 3) AND (r3c3 = 4) AND (r3c5 = 5) AND (r4c4 = 2) AND (r4c8 = 6) AND (r5c3 = 7) AND (r5c7 = 8) AND (r6c2 = 5) AND (r6c6 = 9) AND (r7c5 = 7) AND (r7c7 = 5) AND (r8c1 = 6) AND (r8c2 = 3) AND (r8c4 = 8) AND (r9c2 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 2) AND (r1c3 = 7) AND (r1c5 = 3) AND (r1c6 = 4) AND (r1c8 = 6) AND (r1c9 = 5) AND (r2c6 = 8) AND (r2c9 = 2) AND (r3c3 = 4) AND (r3c7 = 7) AND (r4c1 = 4) AND (r4c9 = 3) AND (r5c1 = 8) AND (r5c3 = 2) AND (r5c7 = 6) AND (r5c8 = 4) AND (r6c2 = 7) AND (r6c9 = 8) AND (r7c2 = 2) AND (r7c3 = 1) AND (r7c5 = 8) AND (r7c8 = 5) AND (r8c1 = 6) AND (r8c2 = 4) AND (r8c5 = 2) AND (r8c6 = 5) AND (r8c7 = 3) AND (r9c1 = 5) AND (r9c6 = 7) AND (r9c9 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c8 = 8) AND (r2c1 = 3) AND (r2c4 = 5) AND (r2c6 = 7) AND (r2c7 = 1) AND (r3c6 = 1) AND (r3c8 = 6) AND (r3c9 = 3) AND (r4c3 = 2) AND (r5c1 = 8) AND (r5c3 = 7) AND (r5c7 = 2) AND (r5c8 = 3) AND (r6c1 = 5) AND (r6c5 = 7) AND (r7c2 = 8) AND (r7c5 = 4) AND (r7c6 = 3) AND (r7c8 = 2) AND (r7c9 = 1) AND (r8c1 = 1) AND (r8c3 = 5) AND (r8c9 = 6) AND (r9c1 = 4) AND (r9c2 = 3) AND (r9c7 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 3) AND (r1c8 = 1) AND (r2c6 = 2) AND (r2c8 = 3) AND (r2c9 = 4) AND (r3c3 = 5) AND (r3c5 = 7) AND (r4c4 = 4) AND (r4c8 = 5) AND (r5c3 = 7) AND (r5c7 = 6) AND (r6c2 = 8) AND (r6c6 = 1) AND (r7c5 = 5) AND (r7c7 = 8) AND (r8c1 = 1) AND (r8c2 = 2) AND (r8c4 = 3) AND (r9c2 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c5 = 3) AND (r1c6 = 1) AND (r2c1 = 3) AND (r2c4 = 4) AND (r2c5 = 2) AND (r2c8 = 6) AND (r3c4 = 6) AND (r3c6 = 9) AND (r4c5 = 7) AND (r4c6 = 3) AND (r4c7 = 4) AND (r5c2 = 7) AND (r5c4 = 1) AND (r5c6 = 2) AND (r5c7 = 5) AND (r5c8 = 3) AND (r6c4 = 5) AND (r6c5 = 4) AND (r6c8 = 1) AND (r7c2 = 1) AND (r7c7 = 3) AND (r8c1 = 5) AND (r8c2 = 3) AND (r8c7 = 6) AND (r8c8 = 9) AND (r9c2 = 6) AND (r9c3 = 9) AND (r9c5 = 1) AND (r9c6 = 4) AND (r9c7 = 2) AND (r9c8 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 8) AND (r1c7 = 4) AND (r2c2 = 2) AND (r2c6 = 1) AND (r2c8 = 9) AND (r3c5 = 7) AND (r3c9 = 5) AND (r4c4 = 4) AND (r4c7 = 8) AND (r5c5 = 5) AND (r5c9 = 7) AND (r6c1 = 1) AND (r6c6 = 9) AND (r6c8 = 2) AND (r7c1 = 9) AND (r7c6 = 6) AND (r7c7 = 1) AND (r7c8 = 3) AND (r8c1 = 2) AND (r9c1 = 6) AND (r9c3 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 3) AND (r1c3 = 4) AND (r1c4 = 6) AND (r1c7 = 9) AND (r1c8 = 2) AND (r1c9 = 1) AND (r2c1 = 2) AND (r3c2 = 1) AND (r3c3 = 9) AND (r3c9 = 5) AND (r4c2 = 4) AND (r4c3 = 2) AND (r4c9 = 9) AND (r5c2 = 9) AND (r5c3 = 6) AND (r6c1 = 3) AND (r6c4 = 9) AND (r6c8 = 6) AND (r7c2 = 2) AND (r7c3 = 1) AND (r7c5 = 4) AND (r7c6 = 9) AND (r7c8 = 5) AND (r8c4 = 5) AND (r8c6 = 6) AND (r8c8 = 1) AND (r9c4 = 2) AND (r9c5 = 1) AND (r9c7 = 7) AND (r9c9 = 3); SELECT * FROM sudoku_memory_combined_view WHERE (r1c9 = 4) AND (r2c2 = 3) AND (r2c3 = 1) AND (r2c6 = 9) AND (r2c9 = 7) AND (r3c1 = 2) AND (r3c2 = 9) AND (r3c6 = 1) AND (r4c2 = 7) AND (r4c6 = 6) AND (r5c6 = 2) AND (r5c9 = 9) AND (r6c4 = 7) AND (r6c5 = 4) AND (r7c1 = 5) AND (r7c5 = 1) AND (r7c8 = 2) AND (r8c2 = 6) AND (r8c5 = 9) AND (r8c8 = 7) AND (r8c9 = 3) AND (r9c3 = 3) AND (r9c8 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 4) AND (r1c6 = 2) AND (r1c7 = 5) AND (r1c8 = 6) AND (r2c4 = 7) AND (r2c9 = 3) AND (r3c2 = 1) AND (r4c1 = 6) AND (r4c5 = 9) AND (r4c6 = 8) AND (r5c5 = 1) AND (r6c9 = 4) AND (r7c7 = 1) AND (r7c8 = 8) AND (r8c1 = 4) AND (r8c4 = 3) AND (r9c1 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 7) AND (r1c4 = 4) AND (r1c5 = 2) AND (r1c6 = 6) AND (r1c7 = 1) AND (r2c2 = 4) AND (r2c4 = 3) AND (r2c5 = 7) AND (r2c8 = 2) AND (r3c3 = 6) AND (r3c5 = 1) AND (r3c6 = 5) AND (r3c8 = 7) AND (r4c1 = 6) AND (r5c2 = 8) AND (r5c4 = 5) AND (r6c1 = 4) AND (r6c2 = 5) AND (r6c3 = 2) AND (r6c5 = 6) AND (r6c6 = 3) AND (r7c1 = 5) AND (r7c4 = 7) AND (r7c9 = 2) AND (r8c1 = 7) AND (r8c9 = 1) AND (r9c1 = 3) AND (r9c3 = 4) AND (r9c4 = 6) AND (r9c5 = 5) AND (r9c6 = 2) AND (r9c9 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 9) AND (r1c7 = 3) AND (r1c9 = 6) AND (r2c1 = 7) AND (r2c4 = 6) AND (r2c6 = 4) AND (r2c7 = 8) AND (r3c1 = 6) AND (r3c2 = 1) AND (r3c5 = 3) AND (r3c9 = 7) AND (r4c1 = 1) AND (r4c2 = 6) AND (r4c7 = 4) AND (r4c9 = 3) AND (r5c6 = 1) AND (r5c7 = 7) AND (r6c2 = 8) AND (r6c4 = 4) AND (r6c5 = 9) AND (r6c8 = 1) AND (r7c2 = 9) AND (r7c5 = 4) AND (r8c9 = 4) AND (r9c1 = 2) AND (r9c2 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 4) AND (r1c2 = 3) AND (r1c5 = 7) AND (r1c6 = 6) AND (r1c7 = 5) AND (r1c8 = 9) AND (r2c2 = 6) AND (r2c3 = 5) AND (r2c5 = 4) AND (r3c4 = 5) AND (r3c5 = 9) AND (r3c7 = 3) AND (r4c2 = 1) AND (r4c6 = 8) AND (r4c7 = 4) AND (r4c8 = 5) AND (r5c1 = 3) AND (r5c2 = 7) AND (r5c4 = 6) AND (r5c6 = 4) AND (r5c7 = 1) AND (r5c9 = 9) AND (r6c5 = 1) AND (r6c6 = 9) AND (r6c8 = 7) AND (r6c9 = 3) AND (r7c2 = 9) AND (r7c5 = 8) AND (r8c2 = 5) AND (r8c5 = 6) AND (r8c6 = 7) AND (r8c7 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 8) AND (r1c2 = 4) AND (r1c6 = 6) AND (r1c8 = 2) AND (r2c3 = 6) AND (r2c9 = 9) AND (r3c7 = 1) AND (r4c5 = 9) AND (r4c8 = 3) AND (r5c1 = 3) AND (r5c2 = 6) AND (r5c7 = 9) AND (r6c3 = 2) AND (r6c4 = 8) AND (r7c2 = 9) AND (r7c7 = 4) AND (r7c8 = 7) AND (r8c2 = 7) AND (r8c3 = 1) AND (r8c5 = 4) AND (r8c7 = 6) AND (r8c9 = 8) AND (r9c1 = 2) AND (r9c9 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 2) AND (r1c4 = 3) AND (r1c6 = 8) AND (r1c8 = 6) AND (r2c1 = 8) AND (r2c5 = 7) AND (r2c9 = 2) AND (r3c3 = 6) AND (r3c4 = 5) AND (r3c6 = 2) AND (r3c7 = 8) AND (r4c1 = 6) AND (r4c3 = 2) AND (r4c7 = 7) AND (r4c9 = 3) AND (r5c2 = 9) AND (r5c8 = 2) AND (r6c1 = 3) AND (r6c3 = 5) AND (r6c7 = 9) AND (r6c9 = 4) AND (r7c3 = 7) AND (r7c4 = 2) AND (r7c6 = 1) AND (r7c7 = 6) AND (r8c1 = 5) AND (r8c5 = 6) AND (r8c9 = 1) AND (r9c2 = 6) AND (r9c4 = 4) AND (r9c6 = 5) AND (r9c8 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 2) AND (r1c3 = 4) AND (r1c8 = 3) AND (r1c9 = 1) AND (r2c1 = 9) AND (r2c3 = 6) AND (r2c4 = 4) AND (r2c5 = 5) AND (r3c3 = 3) AND (r3c5 = 7) AND (r3c8 = 6) AND (r5c1 = 4) AND (r5c8 = 7) AND (r5c9 = 9) AND (r6c4 = 5) AND (r6c5 = 6) AND (r7c1 = 1) AND (r7c4 = 2) AND (r8c1 = 6) AND (r8c2 = 7) AND (r8c5 = 4) AND (r9c5 = 9) AND (r9c6 = 7) AND (r9c8 = 5); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 6) AND (r1c7 = 4) AND (r2c1 = 9) AND (r2c3 = 3) AND (r3c4 = 4) AND (r3c8 = 2) AND (r4c9 = 9) AND (r5c1 = 2) AND (r5c7 = 3) AND (r6c5 = 3) AND (r6c6 = 1) AND (r6c7 = 7) AND (r7c1 = 5) AND (r7c2 = 9) AND (r7c3 = 7) AND (r8c1 = 4) AND (r8c4 = 9) AND (r9c2 = 2) AND (r9c7 = 6) AND (r9c9 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 5) AND (r1c4 = 7) AND (r1c8 = 3) AND (r2c2 = 8) AND (r2c6 = 9) AND (r2c9 = 5) AND (r3c4 = 1) AND (r3c7 = 6) AND (r3c9 = 2) AND (r4c8 = 9) AND (r5c5 = 6) AND (r6c4 = 3) AND (r6c6 = 1) AND (r7c2 = 7) AND (r7c8 = 8) AND (r8c1 = 6) AND (r8c4 = 2) AND (r8c5 = 8) AND (r8c7 = 3) AND (r9c1 = 1) AND (r9c2 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c7 = 7) AND (r2c2 = 4) AND (r2c7 = 1) AND (r2c9 = 3) AND (r3c6 = 9) AND (r3c8 = 6) AND (r3c9 = 5) AND (r4c3 = 4) AND (r5c2 = 3) AND (r5c3 = 7) AND (r5c4 = 2) AND (r5c8 = 9) AND (r6c4 = 1) AND (r7c1 = 7) AND (r7c5 = 1) AND (r7c7 = 6) AND (r8c3 = 5) AND (r8c6 = 7) AND (r8c7 = 2) AND (r9c5 = 6) AND (r9c6 = 5) AND (r9c8 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 2) AND (r1c5 = 3) AND (r1c8 = 5) AND (r2c2 = 8) AND (r2c9 = 1) AND (r3c2 = 9) AND (r4c1 = 5) AND (r4c6 = 1) AND (r4c8 = 3) AND (r5c5 = 8) AND (r5c7 = 9) AND (r6c1 = 2) AND (r7c2 = 4) AND (r7c4 = 6) AND (r7c7 = 8) AND (r8c1 = 7) AND (r8c4 = 5); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 6) AND (r1c5 = 4) AND (r1c6 = 1) AND (r1c7 = 8) AND (r1c9 = 5) AND (r2c3 = 8) AND (r2c6 = 2) AND (r2c7 = 4) AND (r2c9 = 1) AND (r3c1 = 1) AND (r3c3 = 4) AND (r3c4 = 5) AND (r3c5 = 8) AND (r3c8 = 6) AND (r4c3 = 1) AND (r4c5 = 3) AND (r4c9 = 4) AND (r6c6 = 9) AND (r6c9 = 3) AND (r7c2 = 2) AND (r7c3 = 6) AND (r8c1 = 5) AND (r8c3 = 9) AND (r8c5 = 1) AND (r8c6 = 4) AND (r8c8 = 2) AND (r8c9 = 6) AND (r9c1 = 4) AND (r9c5 = 6) AND (r9c9 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 3) AND (r1c4 = 2) AND (r2c1 = 5) AND (r2c5 = 8) AND (r2c7 = 6) AND (r2c9 = 4) AND (r3c9 = 9) AND (r4c1 = 3) AND (r4c4 = 4) AND (r4c5 = 5) AND (r5c3 = 8) AND (r5c4 = 1) AND (r5c5 = 9) AND (r5c6 = 6) AND (r6c1 = 4) AND (r6c5 = 3) AND (r6c7 = 1) AND (r6c9 = 6) AND (r7c1 = 1) AND (r7c4 = 6) AND (r7c7 = 9) AND (r7c8 = 5) AND (r7c9 = 8) AND (r8c4 = 5) AND (r9c1 = 8) AND (r9c2 = 6) AND (r9c7 = 4) AND (r9c9 = 3); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 6) AND (r1c3 = 4) AND (r1c4 = 3) AND (r1c5 = 1) AND (r1c9 = 5) AND (r2c2 = 2) AND (r2c5 = 5) AND (r2c7 = 6) AND (r2c9 = 4) AND (r3c3 = 8) AND (r3c5 = 6) AND (r3c6 = 4) AND (r3c8 = 2) AND (r4c3 = 1) AND (r4c7 = 9) AND (r4c9 = 2) AND (r5c2 = 3) AND (r6c1 = 8) AND (r6c5 = 2) AND (r6c6 = 6) AND (r6c9 = 1) AND (r7c4 = 5) AND (r7c5 = 9) AND (r8c1 = 3) AND (r8c6 = 8) AND (r9c1 = 9) AND (r9c5 = 4) AND (r9c6 = 3) AND (r9c8 = 5); SELECT * FROM sudoku_memory_combined_view WHERE (r1c6 = 1) AND (r1c8 = 7) AND (r1c9 = 3) AND (r2c4 = 5) AND (r2c5 = 6) AND (r2c7 = 8) AND (r2c8 = 4) AND (r3c4 = 3) AND (r3c6 = 8) AND (r3c7 = 6) AND (r4c5 = 5) AND (r4c6 = 2) AND (r4c7 = 7) AND (r4c9 = 6) AND (r5c4 = 7) AND (r5c5 = 1) AND (r5c8 = 3) AND (r7c1 = 2) AND (r7c2 = 7) AND (r7c8 = 6) AND (r7c9 = 8) AND (r8c2 = 4) AND (r8c3 = 5) AND (r8c4 = 1) AND (r9c1 = 6) AND (r9c2 = 8) AND (r9c3 = 3) AND (r9c6 = 7) AND (r9c9 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c5 = 5) AND (r1c8 = 1) AND (r2c1 = 5) AND (r2c2 = 8) AND (r3c5 = 7) AND (r4c4 = 7) AND (r4c5 = 2) AND (r4c6 = 4) AND (r4c7 = 1) AND (r4c8 = 8) AND (r5c1 = 1) AND (r5c5 = 8) AND (r5c9 = 9) AND (r6c2 = 7) AND (r6c4 = 1) AND (r6c5 = 3) AND (r6c8 = 4) AND (r7c1 = 3) AND (r7c3 = 2) AND (r7c5 = 9) AND (r7c7 = 8) AND (r7c8 = 5) AND (r7c9 = 4) AND (r8c2 = 9) AND (r8c3 = 7) AND (r8c7 = 2) AND (r9c1 = 8) AND (r9c3 = 5) AND (r9c6 = 2) AND (r9c8 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 4) AND (r1c6 = 7) AND (r1c9 = 2) AND (r2c1 = 5) AND (r2c2 = 2) AND (r2c4 = 9) AND (r2c5 = 3) AND (r2c7 = 4) AND (r3c4 = 5) AND (r3c9 = 7) AND (r4c1 = 9) AND (r4c2 = 3) AND (r4c9 = 4) AND (r5c9 = 1) AND (r6c6 = 1) AND (r6c7 = 3) AND (r7c3 = 4) AND (r7c5 = 2) AND (r8c1 = 2) AND (r8c2 = 9) AND (r8c5 = 7) AND (r9c1 = 1) AND (r9c5 = 8) AND (r9c6 = 5) AND (r9c8 = 2) AND (r9c9 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 4) AND (r1c7 = 7) AND (r1c8 = 5) AND (r1c9 = 3) AND (r2c2 = 7) AND (r2c3 = 9) AND (r2c6 = 3) AND (r2c7 = 2) AND (r2c8 = 1) AND (r3c3 = 5) AND (r4c5 = 2) AND (r5c3 = 4) AND (r5c5 = 3) AND (r5c7 = 1) AND (r5c9 = 7) AND (r6c1 = 3) AND (r6c3 = 6) AND (r6c4 = 1) AND (r6c7 = 4) AND (r6c8 = 2) AND (r7c1 = 2) AND (r7c3 = 3) AND (r7c6 = 6) AND (r7c7 = 5) AND (r7c9 = 1) AND (r8c2 = 6) AND (r8c3 = 7) AND (r8c5 = 1) AND (r8c8 = 4) AND (r8c9 = 2) AND (r9c7 = 6) AND (r9c8 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 3) AND (r1c3 = 7) AND (r1c8 = 5) AND (r2c3 = 9) AND (r2c5 = 6) AND (r2c8 = 1) AND (r3c6 = 1) AND (r3c7 = 3) AND (r4c2 = 7) AND (r5c3 = 1) AND (r5c4 = 2) AND (r5c6 = 7) AND (r5c9 = 5) AND (r6c5 = 3) AND (r6c7 = 8) AND (r6c9 = 6) AND (r7c6 = 3) AND (r8c4 = 7) AND (r8c5 = 8) AND (r9c1 = 6) AND (r9c8 = 9) AND (r9c9 = 3); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 3) AND (r1c7 = 5) AND (r1c8 = 9) AND (r2c2 = 5) AND (r2c3 = 1) AND (r2c5 = 6) AND (r2c6 = 3) AND (r3c3 = 9) AND (r3c5 = 2) AND (r5c2 = 7) AND (r5c3 = 3) AND (r5c5 = 5) AND (r5c8 = 2) AND (r6c3 = 2) AND (r6c7 = 1) AND (r6c8 = 7) AND (r7c2 = 9) AND (r7c4 = 7) AND (r7c6 = 6) AND (r7c7 = 3) AND (r7c8 = 5) AND (r8c1 = 7) AND (r8c2 = 8) AND (r9c5 = 8) AND (r9c9 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r2c4 = 4) AND (r2c8 = 5) AND (r3c1 = 8) AND (r3c2 = 5) AND (r3c3 = 9) AND (r3c4 = 2) AND (r4c3 = 3) AND (r4c4 = 5) AND (r4c7 = 4) AND (r4c8 = 9) AND (r5c7 = 5) AND (r5c9 = 6) AND (r6c3 = 7) AND (r6c4 = 9) AND (r6c5 = 2) AND (r6c6 = 4) AND (r6c8 = 3) AND (r6c9 = 8) AND (r7c6 = 2) AND (r7c8 = 8) AND (r8c1 = 7) AND (r8c4 = 8) AND (r8c5 = 5) AND (r8c7 = 9) AND (r8c8 = 4) AND (r9c2 = 3) AND (r9c4 = 7) AND (r9c5 = 4) AND (r9c8 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 9) AND (r1c7 = 6) AND (r2c1 = 8) AND (r2c3 = 6) AND (r2c4 = 7) AND (r2c5 = 4) AND (r2c6 = 5) AND (r2c8 = 2) AND (r2c9 = 9) AND (r3c3 = 4) AND (r3c6 = 3) AND (r3c8 = 7) AND (r3c9 = 5) AND (r4c1 = 4) AND (r4c4 = 3) AND (r4c5 = 7) AND (r4c6 = 9) AND (r4c8 = 6) AND (r5c6 = 4) AND (r6c1 = 7) AND (r6c5 = 8) AND (r6c8 = 5) AND (r7c3 = 8) AND (r7c4 = 4) AND (r7c6 = 6) AND (r8c1 = 3) AND (r8c5 = 5) AND (r8c6 = 8) AND (r9c4 = 2) AND (r9c5 = 3) AND (r9c9 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c5 = 7) AND (r3c3 = 3) AND (r3c5 = 2) AND (r3c8 = 5) AND (r4c2 = 6) AND (r4c5 = 4) AND (r4c9 = 2) AND (r5c3 = 8) AND (r5c4 = 5) AND (r5c6 = 9) AND (r6c4 = 6) AND (r7c1 = 6) AND (r7c8 = 9) AND (r8c3 = 2) AND (r8c5 = 3) AND (r8c9 = 4) AND (r9c1 = 4) AND (r9c2 = 7) AND (r9c4 = 8) AND (r9c7 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 3) AND (r1c4 = 4) AND (r1c6 = 6) AND (r2c2 = 9) AND (r2c7 = 7) AND (r4c1 = 6) AND (r4c3 = 4) AND (r4c4 = 1) AND (r5c5 = 7) AND (r5c7 = 2) AND (r5c9 = 9) AND (r6c7 = 5) AND (r7c5 = 3) AND (r7c8 = 8) AND (r8c1 = 5) AND (r8c2 = 2) AND (r9c4 = 8) AND (r9c8 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 7) AND (r1c5 = 2) AND (r2c2 = 8) AND (r2c6 = 6) AND (r3c6 = 3) AND (r3c9 = 6) AND (r4c3 = 3) AND (r4c5 = 4) AND (r4c7 = 7) AND (r4c8 = 8) AND (r5c1 = 2) AND (r5c5 = 1) AND (r6c2 = 6) AND (r6c9 = 5) AND (r7c4 = 1) AND (r7c7 = 3) AND (r7c8 = 7) AND (r8c5 = 5) AND (r9c3 = 8) AND (r9c6 = 7) AND (r9c8 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c8 = 8) AND (r2c1 = 3) AND (r2c2 = 5) AND (r2c3 = 1) AND (r2c5 = 7) AND (r3c6 = 9) AND (r3c7 = 7) AND (r3c9 = 3) AND (r4c3 = 7) AND (r4c4 = 1) AND (r4c6 = 8) AND (r4c7 = 5) AND (r5c5 = 3) AND (r5c7 = 2) AND (r6c2 = 8) AND (r6c6 = 5) AND (r6c8 = 9) AND (r7c7 = 1) AND (r7c8 = 5) AND (r7c9 = 2) AND (r8c3 = 3) AND (r8c4 = 4) AND (r8c6 = 1) AND (r9c4 = 9) AND (r9c5 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c7 = 3) AND (r1c9 = 8) AND (r2c1 = 7) AND (r2c2 = 2) AND (r2c4 = 9) AND (r2c9 = 6) AND (r3c4 = 1) AND (r4c2 = 8) AND (r4c6 = 6) AND (r5c3 = 7) AND (r5c5 = 5) AND (r5c8 = 6) AND (r6c1 = 3) AND (r6c5 = 2) AND (r7c1 = 5) AND (r7c3 = 8) AND (r7c4 = 7) AND (r7c5 = 1) AND (r8c6 = 9) AND (r9c1 = 2) AND (r9c3 = 6) AND (r9c9 = 3); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 5) AND (r1c3 = 2) AND (r1c4 = 9) AND (r2c7 = 8) AND (r3c8 = 4) AND (r3c9 = 6) AND (r4c2 = 1) AND (r4c6 = 2) AND (r4c9 = 3) AND (r5c1 = 3) AND (r5c2 = 7) AND (r6c6 = 4) AND (r7c8 = 7) AND (r8c1 = 6) AND (r8c4 = 5) AND (r8c6 = 1) AND (r9c1 = 4) AND (r9c4 = 3) AND (r9c6 = 9) AND (r9c7 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 7) AND (r1c5 = 6) AND (r1c6 = 4) AND (r1c8 = 2) AND (r1c9 = 5) AND (r2c2 = 5) AND (r2c6 = 9) AND (r2c9 = 1) AND (r3c5 = 2) AND (r3c8 = 4) AND (r3c9 = 9) AND (r4c1 = 5) AND (r4c3 = 6) AND (r4c6 = 3) AND (r4c8 = 1) AND (r5c1 = 4) AND (r5c3 = 2) AND (r6c2 = 1) AND (r7c1 = 3) AND (r7c2 = 6) AND (r7c3 = 9) AND (r7c4 = 4) AND (r7c8 = 5) AND (r8c3 = 5) AND (r8c6 = 6) AND (r9c1 = 7) AND (r9c9 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 9) AND (r1c5 = 6) AND (r1c6 = 5) AND (r1c9 = 7) AND (r2c1 = 5) AND (r2c6 = 3) AND (r2c8 = 6) AND (r2c9 = 8) AND (r3c3 = 8) AND (r3c4 = 4) AND (r3c9 = 9) AND (r4c3 = 2) AND (r5c5 = 5) AND (r5c9 = 3) AND (r6c3 = 6) AND (r6c6 = 7) AND (r7c5 = 9) AND (r7c7 = 2) AND (r8c4 = 3) AND (r8c7 = 4) AND (r9c1 = 6) AND (r9c8 = 3); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 7) AND (r1c4 = 3) AND (r1c8 = 6) AND (r2c5 = 8) AND (r2c7 = 5) AND (r3c2 = 1) AND (r4c1 = 8) AND (r4c3 = 9) AND (r4c4 = 6) AND (r4c7 = 4) AND (r5c4 = 1) AND (r5c6 = 2) AND (r6c1 = 5) AND (r7c4 = 7) AND (r7c8 = 3) AND (r7c9 = 2) AND (r8c1 = 4) AND (r8c5 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c6 = 4) AND (r1c8 = 6) AND (r2c4 = 1) AND (r2c5 = 2) AND (r2c6 = 9) AND (r2c8 = 8) AND (r2c9 = 4) AND (r3c3 = 2) AND (r4c3 = 5) AND (r4c7 = 4) AND (r5c2 = 2) AND (r5c4 = 4) AND (r5c5 = 1) AND (r5c7 = 8) AND (r5c8 = 5) AND (r6c2 = 6) AND (r6c4 = 5) AND (r6c6 = 8) AND (r6c8 = 2) AND (r7c1 = 2) AND (r7c2 = 1) AND (r7c3 = 6) AND (r7c6 = 5) AND (r8c2 = 8) AND (r8c4 = 2) AND (r8c5 = 3) AND (r9c2 = 3) AND (r9c3 = 4) AND (r9c4 = 8) AND (r9c6 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 8) AND (r1c7 = 1) AND (r1c9 = 4) AND (r2c1 = 7) AND (r2c2 = 3) AND (r4c5 = 7) AND (r4c6 = 2) AND (r4c7 = 6) AND (r5c2 = 1) AND (r5c3 = 3) AND (r7c3 = 4) AND (r7c4 = 3) AND (r7c5 = 1) AND (r8c1 = 2) AND (r8c7 = 5) AND (r8c8 = 7) AND (r9c8 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 9) AND (r1c5 = 4) AND (r1c8 = 8) AND (r2c2 = 4) AND (r2c9 = 7) AND (r3c4 = 6) AND (r3c9 = 2) AND (r4c3 = 5) AND (r4c7 = 7) AND (r4c8 = 4) AND (r5c1 = 9) AND (r5c2 = 6) AND (r5c7 = 5) AND (r6c4 = 2) AND (r7c2 = 5) AND (r7c5 = 2) AND (r7c9 = 8) AND (r8c3 = 4) AND (r8c5 = 8) AND (r8c6 = 3) AND (r9c2 = 8) AND (r9c4 = 9) AND (r9c5 = 7) AND (r9c8 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 2) AND (r1c5 = 6) AND (r1c8 = 8) AND (r2c1 = 9) AND (r2c3 = 4) AND (r4c2 = 8) AND (r4c4 = 5) AND (r4c8 = 6) AND (r5c1 = 7) AND (r5c6 = 9) AND (r6c9 = 1) AND (r7c2 = 2) AND (r7c4 = 6) AND (r8c5 = 3) AND (r8c7 = 9) AND (r9c1 = 1) AND (r9c7 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 4) AND (r1c3 = 8) AND (r1c4 = 9) AND (r1c6 = 7) AND (r1c7 = 1) AND (r3c4 = 4) AND (r3c5 = 3) AND (r3c6 = 1) AND (r4c6 = 4) AND (r5c5 = 9) AND (r5c7 = 7) AND (r6c1 = 6) AND (r6c5 = 2) AND (r6c6 = 3) AND (r7c2 = 7) AND (r7c6 = 8) AND (r7c7 = 3) AND (r7c9 = 9) AND (r8c1 = 1) AND (r8c3 = 3) AND (r8c5 = 7) AND (r8c6 = 2) AND (r8c7 = 8) AND (r8c9 = 4) AND (r9c2 = 8) AND (r9c3 = 4) AND (r9c7 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 7) AND (r1c3 = 5) AND (r1c7 = 8) AND (r1c8 = 2) AND (r2c1 = 2) AND (r2c2 = 9) AND (r2c3 = 8) AND (r2c4 = 7) AND (r3c1 = 4) AND (r3c2 = 3) AND (r3c8 = 5) AND (r3c9 = 9) AND (r4c1 = 8) AND (r4c4 = 3) AND (r4c5 = 4) AND (r4c6 = 6) AND (r5c4 = 2) AND (r5c7 = 3) AND (r6c5 = 5) AND (r6c6 = 7) AND (r7c5 = 6) AND (r7c6 = 4) AND (r8c4 = 8) AND (r8c6 = 9) AND (r8c8 = 4) AND (r9c4 = 5) AND (r9c5 = 3) AND (r9c7 = 6) AND (r9c8 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 1) AND (r1c8 = 8) AND (r2c8 = 6) AND (r3c3 = 8) AND (r3c4 = 4) AND (r3c7 = 1) AND (r4c1 = 5) AND (r4c3 = 6) AND (r4c7 = 4) AND (r5c5 = 9) AND (r5c8 = 5) AND (r5c9 = 7) AND (r6c5 = 8) AND (r6c6 = 4) AND (r7c4 = 8) AND (r7c6 = 7) AND (r7c7 = 2) AND (r8c2 = 2) AND (r8c3 = 7) AND (r8c5 = 1) AND (r9c2 = 5) AND (r9c4 = 6) AND (r9c6 = 2) AND (r9c7 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 6) AND (r1c4 = 3) AND (r1c6 = 1) AND (r2c5 = 8) AND (r2c9 = 1) AND (r3c2 = 8) AND (r3c4 = 9) AND (r3c5 = 5) AND (r3c6 = 7) AND (r3c8 = 3) AND (r4c1 = 9) AND (r4c3 = 8) AND (r4c5 = 3) AND (r4c6 = 4) AND (r4c8 = 6) AND (r5c6 = 9) AND (r6c4 = 1) AND (r6c5 = 7) AND (r6c6 = 8) AND (r6c8 = 9) AND (r6c9 = 5) AND (r7c1 = 8) AND (r7c2 = 6) AND (r7c6 = 5) AND (r7c7 = 7) AND (r7c8 = 1) AND (r8c1 = 7) AND (r8c3 = 1) AND (r8c6 = 3) AND (r8c7 = 5) AND (r8c9 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c8 = 4) AND (r2c1 = 6) AND (r2c4 = 3) AND (r2c5 = 8) AND (r2c9 = 7) AND (r3c4 = 7) AND (r3c5 = 9) AND (r3c6 = 6) AND (r4c4 = 6) AND (r4c8 = 3) AND (r5c5 = 1) AND (r6c3 = 7) AND (r6c4 = 4) AND (r6c9 = 2) AND (r7c2 = 4) AND (r7c4 = 8) AND (r7c9 = 6) AND (r8c1 = 3) AND (r8c2 = 1) AND (r9c2 = 9) AND (r9c7 = 2) AND (r9c8 = 1) AND (r9c9 = 3); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 1) AND (r1c7 = 6) AND (r2c2 = 4) AND (r2c3 = 3) AND (r2c8 = 8) AND (r2c9 = 5) AND (r3c1 = 6) AND (r3c4 = 5) AND (r3c9 = 2) AND (r4c6 = 3) AND (r4c7 = 2) AND (r5c3 = 5) AND (r5c5 = 1) AND (r5c6 = 7) AND (r5c8 = 6) AND (r5c9 = 8) AND (r6c4 = 8) AND (r6c6 = 5) AND (r6c9 = 1) AND (r7c3 = 2) AND (r7c6 = 6) AND (r7c7 = 1) AND (r7c8 = 3) AND (r7c9 = 4) AND (r8c1 = 4) AND (r8c6 = 1) AND (r8c8 = 2) AND (r8c9 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 4) AND (r1c5 = 2) AND (r1c6 = 9) AND (r1c7 = 3) AND (r1c8 = 6) AND (r2c1 = 3) AND (r2c2 = 8) AND (r2c4 = 1) AND (r2c5 = 4) AND (r2c8 = 2) AND (r3c2 = 9) AND (r4c2 = 1) AND (r4c3 = 9) AND (r4c4 = 8) AND (r4c7 = 4) AND (r5c4 = 4) AND (r5c5 = 9) AND (r5c9 = 7) AND (r6c6 = 3) AND (r7c1 = 8) AND (r7c3 = 6) AND (r8c3 = 7) AND (r8c7 = 8) AND (r9c6 = 2) AND (r9c8 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 1) AND (r1c8 = 6) AND (r2c1 = 6) AND (r2c5 = 7) AND (r2c6 = 2) AND (r3c9 = 9) AND (r4c1 = 1) AND (r4c2 = 8) AND (r4c4 = 2) AND (r4c7 = 5) AND (r6c6 = 5) AND (r6c8 = 9) AND (r6c9 = 4) AND (r7c1 = 7) AND (r7c2 = 5) AND (r7c7 = 9) AND (r8c1 = 4) AND (r8c6 = 6) AND (r8c7 = 8) AND (r8c8 = 5) AND (r9c3 = 6) AND (r9c5 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 6) AND (r1c6 = 7) AND (r1c7 = 5) AND (r2c5 = 5) AND (r2c8 = 6) AND (r2c9 = 4) AND (r3c2 = 5) AND (r3c5 = 6) AND (r3c7 = 9) AND (r3c8 = 8) AND (r3c9 = 1) AND (r4c1 = 1) AND (r5c3 = 7) AND (r5c4 = 9) AND (r5c9 = 2) AND (r6c2 = 9) AND (r6c7 = 1) AND (r7c3 = 4) AND (r7c5 = 1) AND (r7c6 = 5) AND (r7c9 = 9) AND (r8c1 = 8) AND (r8c5 = 7) AND (r8c9 = 6) AND (r9c6 = 2) AND (r9c8 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 9) AND (r1c5 = 6) AND (r2c2 = 2) AND (r2c3 = 7) AND (r2c5 = 9) AND (r2c6 = 1) AND (r2c9 = 5) AND (r3c3 = 3) AND (r3c4 = 7) AND (r3c6 = 8) AND (r4c8 = 3) AND (r5c1 = 5) AND (r5c3 = 6) AND (r5c5 = 2) AND (r5c6 = 9) AND (r5c7 = 7) AND (r6c1 = 2) AND (r6c3 = 1) AND (r6c6 = 7) AND (r7c1 = 3) AND (r7c3 = 9) AND (r7c6 = 6) AND (r7c7 = 1) AND (r7c8 = 2) AND (r8c2 = 6) AND (r8c3 = 5) AND (r8c5 = 1) AND (r8c6 = 2) AND (r9c1 = 1) AND (r9c4 = 9) AND (r9c5 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 3) AND (r1c7 = 7) AND (r1c8 = 6) AND (r2c1 = 8) AND (r2c5 = 2) AND (r2c6 = 6) AND (r2c8 = 5) AND (r3c1 = 4) AND (r3c2 = 5) AND (r4c8 = 1) AND (r5c3 = 2) AND (r5c4 = 8) AND (r5c6 = 5) AND (r5c8 = 3) AND (r5c9 = 7) AND (r6c9 = 8) AND (r7c1 = 2) AND (r7c3 = 8) AND (r7c4 = 6) AND (r8c2 = 3) AND (r8c4 = 5) AND (r8c7 = 6) AND (r8c8 = 2) AND (r9c3 = 7) AND (r9c6 = 2) AND (r9c9 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 9) AND (r2c2 = 1) AND (r2c5 = 8) AND (r2c6 = 6) AND (r2c7 = 4) AND (r3c2 = 4) AND (r4c3 = 8) AND (r4c7 = 1) AND (r4c8 = 3) AND (r5c1 = 5) AND (r5c2 = 3) AND (r6c2 = 7) AND (r6c3 = 1) AND (r6c5 = 3) AND (r6c7 = 5) AND (r7c3 = 7) AND (r7c4 = 4) AND (r7c8 = 1) AND (r8c2 = 5) AND (r8c3 = 4) AND (r8c4 = 7) AND (r8c5 = 9) AND (r8c7 = 6) AND (r8c9 = 8) AND (r9c2 = 6) AND (r9c3 = 9) AND (r9c4 = 8) AND (r9c5 = 5) AND (r9c6 = 1) AND (r9c7 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 7) AND (r1c3 = 8) AND (r1c5 = 2) AND (r2c8 = 9) AND (r2c9 = 1) AND (r3c1 = 3) AND (r4c2 = 4) AND (r4c3 = 6) AND (r5c5 = 3) AND (r5c7 = 7) AND (r6c4 = 5) AND (r7c2 = 5) AND (r7c4 = 9) AND (r7c6 = 6) AND (r8c4 = 4) AND (r8c8 = 1) AND (r9c1 = 2) AND (r9c7 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c7 = 3) AND (r1c9 = 2) AND (r2c3 = 8) AND (r3c5 = 5) AND (r4c9 = 4) AND (r5c2 = 5) AND (r5c5 = 7) AND (r5c8 = 2) AND (r6c2 = 7) AND (r6c4 = 3) AND (r6c5 = 8) AND (r6c6 = 4) AND (r6c8 = 5) AND (r7c2 = 9) AND (r7c3 = 7) AND (r7c6 = 8) AND (r7c9 = 5) AND (r8c2 = 8) AND (r8c3 = 2) AND (r8c5 = 1) AND (r8c6 = 7) AND (r8c8 = 4) AND (r9c2 = 1) AND (r9c3 = 5) AND (r9c4 = 4) AND (r9c5 = 2) AND (r9c9 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 7) AND (r1c6 = 5) AND (r2c1 = 6) AND (r2c9 = 4) AND (r3c1 = 8) AND (r3c2 = 5) AND (r3c6 = 7) AND (r4c6 = 8) AND (r4c9 = 6) AND (r5c1 = 9) AND (r5c2 = 6) AND (r5c5 = 4) AND (r5c7 = 5) AND (r6c3 = 1) AND (r6c6 = 3) AND (r6c7 = 8) AND (r7c3 = 4) AND (r7c5 = 7) AND (r8c1 = 3) AND (r8c4 = 8) AND (r8c7 = 9) AND (r8c9 = 7) AND (r9c2 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 8) AND (r1c5 = 7) AND (r1c8 = 2) AND (r2c7 = 6) AND (r2c9 = 4) AND (r3c3 = 6) AND (r3c4 = 9) AND (r3c6 = 5) AND (r3c7 = 3) AND (r4c4 = 5) AND (r4c6 = 7) AND (r5c5 = 9) AND (r5c8 = 8) AND (r5c9 = 2) AND (r6c7 = 5) AND (r7c1 = 2) AND (r7c2 = 3) AND (r7c6 = 4) AND (r7c9 = 9) AND (r8c1 = 4) AND (r8c4 = 7) AND (r8c5 = 6) AND (r8c9 = 5) AND (r9c1 = 5) AND (r9c5 = 3) AND (r9c6 = 9) AND (r9c8 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 6) AND (r1c4 = 8) AND (r1c6 = 9) AND (r1c9 = 5) AND (r2c1 = 5) AND (r2c6 = 4) AND (r3c1 = 9) AND (r3c2 = 2) AND (r3c7 = 6) AND (r4c3 = 1) AND (r4c7 = 3) AND (r5c3 = 3) AND (r5c5 = 8) AND (r5c9 = 6) AND (r6c1 = 6) AND (r6c4 = 1) AND (r6c5 = 9) AND (r6c8 = 5) AND (r6c9 = 8) AND (r7c9 = 3) AND (r8c6 = 2) AND (r9c4 = 6) AND (r9c7 = 1) AND (r9c9 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c7 = 6) AND (r1c9 = 7) AND (r2c4 = 7) AND (r2c5 = 9) AND (r2c8 = 8) AND (r2c9 = 3) AND (r3c5 = 8) AND (r3c7 = 5) AND (r3c8 = 4) AND (r4c2 = 4) AND (r4c3 = 3) AND (r4c5 = 1) AND (r4c9 = 5) AND (r5c3 = 5) AND (r5c8 = 6) AND (r6c2 = 6) AND (r6c5 = 3) AND (r6c7 = 4) AND (r7c1 = 6) AND (r7c4 = 3) AND (r7c6 = 9) AND (r7c7 = 8) AND (r8c6 = 5) AND (r8c8 = 9) AND (r9c1 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c6 = 2) AND (r2c2 = 4) AND (r2c6 = 6) AND (r2c8 = 7) AND (r2c9 = 1) AND (r3c3 = 9) AND (r3c4 = 3) AND (r3c7 = 4) AND (r4c4 = 9) AND (r4c5 = 4) AND (r5c3 = 6) AND (r5c6 = 1) AND (r5c9 = 7) AND (r6c3 = 1) AND (r6c5 = 2) AND (r6c6 = 7) AND (r7c1 = 7) AND (r7c3 = 4) AND (r7c4 = 1) AND (r7c5 = 6) AND (r7c8 = 9) AND (r7c9 = 5) AND (r8c1 = 9) AND (r9c1 = 6) AND (r9c2 = 1) AND (r9c5 = 5) AND (r9c8 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 7) AND (r1c6 = 1) AND (r1c8 = 4) AND (r2c1 = 8) AND (r2c3 = 9) AND (r2c4 = 2) AND (r2c8 = 1) AND (r3c4 = 8) AND (r3c6 = 7) AND (r3c7 = 2) AND (r3c9 = 5) AND (r4c1 = 5) AND (r5c3 = 4) AND (r5c4 = 6) AND (r5c8 = 8) AND (r6c3 = 7) AND (r6c4 = 4) AND (r7c4 = 9) AND (r7c8 = 6) AND (r7c9 = 8) AND (r8c1 = 9) AND (r8c3 = 5) AND (r8c4 = 1) AND (r8c6 = 8) AND (r8c7 = 4) AND (r8c8 = 7) AND (r9c1 = 4) AND (r9c3 = 8) AND (r9c5 = 2) AND (r9c8 = 5) AND (r9c9 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 7) AND (r1c3 = 8) AND (r1c9 = 4) AND (r2c1 = 6) AND (r2c3 = 2) AND (r2c7 = 5) AND (r2c8 = 8) AND (r3c1 = 5) AND (r3c2 = 4) AND (r3c5 = 2) AND (r3c7 = 1) AND (r3c8 = 6) AND (r3c9 = 7) AND (r4c7 = 8) AND (r4c8 = 4) AND (r5c1 = 2) AND (r5c7 = 7) AND (r5c9 = 5) AND (r6c1 = 4) AND (r6c2 = 8) AND (r6c3 = 5) AND (r6c6 = 1) AND (r6c8 = 2) AND (r7c1 = 7) AND (r7c4 = 3) AND (r7c6 = 4) AND (r8c9 = 2) AND (r9c1 = 8) AND (r9c2 = 5) AND (r9c6 = 6) AND (r9c7 = 4) AND (r9c8 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 5) AND (r1c9 = 3) AND (r2c3 = 6) AND (r2c6 = 1) AND (r2c8 = 8) AND (r3c4 = 4) AND (r3c7 = 6) AND (r3c9 = 2) AND (r4c9 = 1) AND (r5c4 = 9) AND (r5c6 = 8) AND (r5c7 = 5) AND (r6c5 = 3) AND (r6c6 = 6) AND (r6c7 = 8) AND (r7c1 = 4) AND (r7c7 = 1) AND (r7c8 = 9) AND (r8c1 = 8) AND (r8c3 = 5) AND (r8c5 = 1) AND (r8c8 = 4) AND (r9c4 = 6) AND (r9c6 = 3); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 9) AND (r1c5 = 3) AND (r2c3 = 6) AND (r2c4 = 2) AND (r2c6 = 8) AND (r3c4 = 9) AND (r3c5 = 7) AND (r3c9 = 5) AND (r5c1 = 2) AND (r5c3 = 9) AND (r5c4 = 8) AND (r5c6 = 3) AND (r6c4 = 6) AND (r6c6 = 7) AND (r6c9 = 9) AND (r7c1 = 7) AND (r7c2 = 5) AND (r7c8 = 8) AND (r7c9 = 4) AND (r8c2 = 4) AND (r8c3 = 8) AND (r8c5 = 5) AND (r8c7 = 6) AND (r8c9 = 3) AND (r9c3 = 2) AND (r9c8 = 5) AND (r9c9 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 1) AND (r1c5 = 2) AND (r2c4 = 1) AND (r2c9 = 8) AND (r3c2 = 8) AND (r3c4 = 3) AND (r3c6 = 7) AND (r3c8 = 1) AND (r4c2 = 5) AND (r4c3 = 7) AND (r4c8 = 3) AND (r5c3 = 2) AND (r5c7 = 6) AND (r6c1 = 8) AND (r6c7 = 5) AND (r6c8 = 7) AND (r6c9 = 4) AND (r7c2 = 7) AND (r7c9 = 3) AND (r8c3 = 4) AND (r8c4 = 7) AND (r8c7 = 1) AND (r8c8 = 2) AND (r9c1 = 2) AND (r9c3 = 5) AND (r9c7 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 8) AND (r1c2 = 1) AND (r1c6 = 3) AND (r1c7 = 9) AND (r2c2 = 6) AND (r2c8 = 8) AND (r2c9 = 2) AND (r3c1 = 2) AND (r3c4 = 7) AND (r3c7 = 3) AND (r4c2 = 8) AND (r4c5 = 3) AND (r4c6 = 6) AND (r5c2 = 9) AND (r5c5 = 1) AND (r5c7 = 4) AND (r5c8 = 3) AND (r6c3 = 6) AND (r6c6 = 9) AND (r7c3 = 2) AND (r8c5 = 8) AND (r8c8 = 7) AND (r9c9 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 7) AND (r1c5 = 8) AND (r1c7 = 4) AND (r2c1 = 3) AND (r2c9 = 2) AND (r4c1 = 1) AND (r4c3 = 6) AND (r4c4 = 3) AND (r5c7 = 8) AND (r5c8 = 5) AND (r6c1 = 2) AND (r7c2 = 8) AND (r7c3 = 4) AND (r7c8 = 3) AND (r8c4 = 2) AND (r8c6 = 1) AND (r9c5 = 5); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 4) AND (r1c3 = 9) AND (r2c6 = 7) AND (r3c2 = 6) AND (r3c7 = 4) AND (r4c1 = 9) AND (r4c2 = 1) AND (r4c4 = 7) AND (r4c8 = 3) AND (r4c9 = 6) AND (r5c4 = 3) AND (r5c5 = 5) AND (r5c7 = 1) AND (r5c8 = 4) AND (r6c1 = 2) AND (r7c4 = 5) AND (r7c8 = 7) AND (r8c2 = 3) AND (r8c3 = 6) AND (r8c5 = 2) AND (r9c2 = 2) AND (r9c4 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c5 = 5) AND (r1c8 = 4) AND (r1c9 = 6) AND (r2c6 = 1) AND (r2c8 = 7) AND (r3c1 = 3) AND (r3c3 = 6) AND (r3c6 = 9) AND (r3c7 = 5) AND (r3c9 = 1) AND (r4c2 = 5) AND (r4c5 = 9) AND (r4c6 = 4) AND (r5c4 = 2) AND (r6c1 = 9) AND (r6c5 = 7) AND (r6c9 = 3) AND (r7c1 = 4) AND (r7c5 = 6) AND (r7c6 = 7) AND (r7c8 = 2) AND (r7c9 = 5) AND (r9c1 = 6) AND (r9c4 = 5) AND (r9c5 = 1) AND (r9c6 = 3) AND (r9c9 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 7) AND (r1c4 = 2) AND (r1c6 = 4) AND (r1c8 = 1) AND (r2c1 = 4) AND (r2c2 = 9) AND (r2c4 = 1) AND (r2c6 = 7) AND (r2c8 = 5) AND (r2c9 = 2) AND (r3c5 = 5) AND (r4c1 = 1) AND (r4c2 = 3) AND (r4c8 = 9) AND (r4c9 = 7) AND (r5c3 = 9) AND (r5c7 = 2) AND (r6c1 = 5) AND (r6c2 = 4) AND (r6c8 = 6) AND (r6c9 = 3) AND (r7c5 = 2) AND (r8c1 = 2) AND (r8c2 = 5) AND (r8c4 = 7) AND (r8c6 = 1) AND (r8c8 = 8) AND (r8c9 = 6) AND (r9c2 = 1) AND (r9c4 = 6) AND (r9c6 = 3) AND (r9c8 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 5) AND (r1c6 = 2) AND (r1c9 = 4) AND (r2c1 = 7) AND (r2c3 = 2) AND (r2c6 = 4) AND (r2c7 = 3) AND (r2c8 = 5) AND (r3c2 = 1) AND (r3c6 = 3) AND (r3c7 = 9) AND (r4c1 = 3) AND (r4c3 = 7) AND (r4c4 = 5) AND (r4c6 = 8) AND (r4c7 = 2) AND (r6c7 = 7) AND (r6c9 = 8) AND (r7c2 = 7) AND (r7c3 = 1) AND (r7c5 = 8) AND (r7c6 = 5) AND (r7c7 = 4) AND (r8c1 = 4) AND (r8c3 = 3) AND (r8c9 = 2) AND (r9c1 = 2) AND (r9c3 = 8) AND (r9c5 = 3) AND (r9c9 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 8) AND (r1c8 = 1) AND (r2c6 = 2) AND (r2c8 = 3) AND (r2c9 = 4) AND (r3c3 = 2) AND (r3c5 = 5) AND (r4c4 = 4) AND (r4c8 = 6) AND (r5c3 = 7) AND (r5c7 = 8) AND (r6c2 = 5) AND (r7c5 = 7) AND (r7c7 = 5) AND (r8c1 = 9) AND (r8c2 = 4) AND (r8c4 = 1) AND (r9c2 = 6) AND (r9c9 = 3); SELECT * FROM sudoku_memory_combined_view WHERE (r1c9 = 1) AND (r2c6 = 4) AND (r2c8 = 8) AND (r3c2 = 4) AND (r3c4 = 6) AND (r3c6 = 1) AND (r3c8 = 2) AND (r4c1 = 5) AND (r4c2 = 6) AND (r4c3 = 2) AND (r4c5 = 7) AND (r4c7 = 3) AND (r4c8 = 4) AND (r5c1 = 1) AND (r5c3 = 7) AND (r5c6 = 3) AND (r5c9 = 2) AND (r6c1 = 4) AND (r6c2 = 3) AND (r6c5 = 6) AND (r6c8 = 7) AND (r7c9 = 7) AND (r8c6 = 6) AND (r8c7 = 8) AND (r8c9 = 4) AND (r9c1 = 3) AND (r9c4 = 8) AND (r9c6 = 7) AND (r9c7 = 2) AND (r9c8 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c6 = 3) AND (r2c1 = 7) AND (r2c7 = 8) AND (r2c8 = 5) AND (r3c2 = 8) AND (r3c4 = 4) AND (r3c5 = 9) AND (r3c8 = 7) AND (r4c3 = 4) AND (r5c2 = 3) AND (r5c4 = 1) AND (r5c5 = 8) AND (r6c1 = 6) AND (r6c3 = 9) AND (r6c9 = 4) AND (r8c3 = 6) AND (r8c5 = 5) AND (r8c9 = 3) AND (r9c5 = 6) AND (r9c9 = 1); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 9) AND (r1c6 = 4) AND (r1c8 = 8) AND (r1c9 = 6) AND (r2c3 = 6) AND (r2c4 = 3) AND (r2c7 = 7) AND (r3c2 = 4) AND (r3c3 = 8) AND (r3c8 = 3) AND (r3c9 = 5) AND (r4c2 = 9) AND (r4c4 = 4) AND (r5c3 = 1) AND (r6c1 = 4) AND (r6c3 = 5) AND (r6c4 = 9) AND (r6c6 = 6) AND (r7c1 = 7) AND (r7c2 = 8) AND (r7c3 = 4) AND (r7c5 = 6) AND (r7c6 = 9) AND (r7c9 = 3) AND (r8c6 = 3) AND (r9c1 = 6) AND (r9c4 = 1) AND (r9c5 = 4) AND (r9c6 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 5) AND (r1c4 = 9) AND (r1c7 = 1) AND (r2c4 = 4) AND (r2c7 = 9) AND (r3c1 = 6) AND (r3c2 = 3) AND (r3c5 = 2) AND (r3c7 = 5) AND (r4c1 = 4) AND (r4c9 = 6) AND (r5c3 = 1) AND (r5c5 = 3) AND (r6c8 = 3) AND (r6c9 = 4) AND (r7c1 = 7) AND (r7c2 = 2) AND (r7c4 = 6) AND (r8c4 = 7) AND (r9c8 = 5); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 2) AND (r1c5 = 1) AND (r1c7 = 4) AND (r2c3 = 3) AND (r2c5 = 9) AND (r2c7 = 2) AND (r2c8 = 5) AND (r3c1 = 7) AND (r3c3 = 5) AND (r4c4 = 9) AND (r4c7 = 6) AND (r4c9 = 3) AND (r5c1 = 9) AND (r6c3 = 2) AND (r6c6 = 5) AND (r7c5 = 2) AND (r7c8 = 4) AND (r8c6 = 9) AND (r8c8 = 2) AND (r8c9 = 7) AND (r9c3 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 3) AND (r1c6 = 5) AND (r2c1 = 4) AND (r2c4 = 8) AND (r2c5 = 6) AND (r2c6 = 9) AND (r2c9 = 5) AND (r3c1 = 8) AND (r4c3 = 9) AND (r4c6 = 2) AND (r4c8 = 5) AND (r4c9 = 6) AND (r5c1 = 1) AND (r5c3 = 2) AND (r5c8 = 3) AND (r6c1 = 6) AND (r6c2 = 8) AND (r6c4 = 9) AND (r6c5 = 3) AND (r6c8 = 2) AND (r6c9 = 4) AND (r7c2 = 3) AND (r7c3 = 8) AND (r7c4 = 6) AND (r7c9 = 9) AND (r8c1 = 5) AND (r9c3 = 6) AND (r9c9 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 7) AND (r1c9 = 1) AND (r2c3 = 2) AND (r2c4 = 9) AND (r2c8 = 5) AND (r3c1 = 8) AND (r3c7 = 4) AND (r4c3 = 6) AND (r4c4 = 2) AND (r4c5 = 5) AND (r5c6 = 7) AND (r6c4 = 3) AND (r6c6 = 6) AND (r6c8 = 9) AND (r7c1 = 4) AND (r7c7 = 7) AND (r8c2 = 1) AND (r8c9 = 8) AND (r9c3 = 5) AND (r9c5 = 3) AND (r9c8 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 3) AND (r1c4 = 5) AND (r1c8 = 8) AND (r2c1 = 7) AND (r2c5 = 2) AND (r3c3 = 9) AND (r3c6 = 7) AND (r4c4 = 2) AND (r4c6 = 1) AND (r5c1 = 5) AND (r5c2 = 2) AND (r6c2 = 4) AND (r6c5 = 8) AND (r6c7 = 7) AND (r7c4 = 3) AND (r7c8 = 2) AND (r8c5 = 9) AND (r8c6 = 8) AND (r8c7 = 3) AND (r9c2 = 1) AND (r9c3 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 8) AND (r1c2 = 1) AND (r1c3 = 2) AND (r1c5 = 3) AND (r2c1 = 4) AND (r2c7 = 5) AND (r3c4 = 7) AND (r3c7 = 2) AND (r3c8 = 3) AND (r4c1 = 2) AND (r4c4 = 8) AND (r4c5 = 5) AND (r5c1 = 3) AND (r5c4 = 1) AND (r5c5 = 6) AND (r5c6 = 7) AND (r5c7 = 8) AND (r5c9 = 5) AND (r6c4 = 4) AND (r6c8 = 7) AND (r6c9 = 6) AND (r7c1 = 1) AND (r7c5 = 7) AND (r8c2 = 6) AND (r8c3 = 5) AND (r8c9 = 8) AND (r9c9 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c7 = 8) AND (r2c1 = 2) AND (r2c2 = 8) AND (r2c3 = 3) AND (r2c7 = 4) AND (r2c8 = 1) AND (r3c4 = 2) AND (r4c3 = 1) AND (r4c4 = 3) AND (r4c9 = 6) AND (r5c3 = 2) AND (r5c4 = 1) AND (r5c6 = 6) AND (r5c8 = 5) AND (r5c9 = 4) AND (r6c6 = 5) AND (r6c8 = 7) AND (r7c1 = 1) AND (r7c3 = 5) AND (r8c4 = 4) AND (r8c8 = 3) AND (r8c9 = 1) AND (r9c1 = 3) AND (r9c3 = 8) AND (r9c6 = 1) AND (r9c7 = 6) AND (r9c8 = 2) AND (r9c9 = 5); SELECT * FROM sudoku_memory_combined_view WHERE (r1c6 = 5) AND (r1c9 = 1) AND (r2c2 = 6) AND (r2c5 = 7) AND (r2c7 = 2) AND (r3c2 = 1) AND (r3c3 = 7) AND (r4c3 = 3) AND (r4c4 = 5) AND (r4c5 = 2) AND (r5c4 = 8) AND (r5c5 = 3) AND (r5c7 = 1) AND (r5c9 = 4) AND (r7c4 = 7) AND (r7c9 = 5) AND (r8c3 = 2) AND (r8c6 = 1) AND (r8c9 = 3) AND (r9c1 = 3) AND (r9c2 = 4) AND (r9c9 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 7) AND (r1c4 = 5) AND (r1c6 = 8) AND (r1c8 = 6) AND (r2c1 = 8) AND (r2c5 = 1) AND (r2c9 = 7) AND (r3c2 = 9) AND (r3c8 = 8) AND (r4c3 = 8) AND (r4c4 = 6) AND (r4c6 = 9) AND (r4c7 = 7) AND (r5c2 = 5) AND (r5c3 = 9) AND (r5c4 = 2) AND (r5c6 = 7) AND (r5c7 = 8) AND (r5c8 = 1) AND (r6c3 = 7) AND (r6c4 = 1) AND (r6c6 = 3) AND (r6c7 = 5) AND (r7c2 = 3) AND (r7c8 = 4) AND (r8c1 = 7) AND (r8c5 = 6) AND (r8c9 = 2) AND (r9c2 = 6) AND (r9c4 = 8) AND (r9c6 = 4) AND (r9c8 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 8) AND (r1c7 = 7) AND (r1c8 = 4) AND (r2c1 = 5) AND (r2c3 = 1) AND (r3c1 = 3) AND (r3c8 = 9) AND (r4c2 = 9) AND (r4c4 = 2) AND (r4c7 = 5) AND (r5c4 = 6) AND (r5c5 = 8) AND (r6c7 = 3) AND (r7c5 = 3) AND (r7c6 = 1) AND (r8c2 = 2) AND (r8c9 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 3) AND (r1c7 = 5) AND (r1c9 = 9) AND (r2c1 = 9) AND (r2c2 = 8) AND (r2c3 = 6) AND (r2c5 = 2) AND (r2c7 = 3) AND (r3c3 = 2) AND (r3c9 = 1) AND (r4c7 = 1) AND (r4c8 = 7) AND (r5c4 = 5) AND (r5c6 = 7) AND (r7c1 = 7) AND (r7c6 = 3) AND (r7c7 = 8) AND (r7c8 = 6) AND (r8c3 = 8) AND (r8c4 = 2) AND (r8c5 = 6) AND (r9c2 = 5) AND (r9c9 = 3); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 4) AND (r1c9 = 3) AND (r2c2 = 2) AND (r2c5 = 5) AND (r2c9 = 9) AND (r3c2 = 9) AND (r3c3 = 5) AND (r3c5 = 3) AND (r3c8 = 8) AND (r4c4 = 4) AND (r6c1 = 6) AND (r6c6 = 9) AND (r6c7 = 7) AND (r7c1 = 4) AND (r7c4 = 7) AND (r7c7 = 6) AND (r7c8 = 2) AND (r8c4 = 6) AND (r8c9 = 5) AND (r9c1 = 3) AND (r9c4 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 9) AND (r2c5 = 6) AND (r2c8 = 1) AND (r3c6 = 5) AND (r4c2 = 1) AND (r4c6 = 9) AND (r5c1 = 8) AND (r5c5 = 4) AND (r6c1 = 4) AND (r6c2 = 2) AND (r6c4 = 8) AND (r6c8 = 3) AND (r7c4 = 9) AND (r7c7 = 5) AND (r7c9 = 3) AND (r8c2 = 8) AND (r8c3 = 5) AND (r8c4 = 3) AND (r8c9 = 1) AND (r9c4 = 1) AND (r9c6 = 2) AND (r9c8 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c8 = 1) AND (r2c1 = 3) AND (r2c2 = 2) AND (r2c4 = 9) AND (r2c9 = 5) AND (r3c2 = 8) AND (r3c4 = 4) AND (r3c5 = 5) AND (r4c3 = 2) AND (r4c4 = 5) AND (r4c6 = 3) AND (r5c8 = 5) AND (r5c9 = 9) AND (r6c1 = 7) AND (r6c9 = 3) AND (r7c3 = 7) AND (r8c1 = 5) AND (r8c5 = 4) AND (r8c7 = 1) AND (r9c2 = 9) AND (r9c3 = 1) AND (r9c4 = 3) AND (r9c7 = 5) AND (r9c8 = 2) AND (r9c9 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 8) AND (r1c4 = 5) AND (r1c8 = 4) AND (r2c1 = 5) AND (r2c4 = 3) AND (r2c6 = 8) AND (r3c1 = 2) AND (r3c7 = 9) AND (r4c2 = 6) AND (r4c5 = 7) AND (r5c1 = 4) AND (r5c2 = 3) AND (r5c7 = 6) AND (r6c3 = 5) AND (r6c5 = 8) AND (r7c3 = 9) AND (r7c9 = 6) AND (r8c1 = 7) AND (r8c7 = 5) AND (r9c2 = 8) AND (r9c4 = 4) AND (r9c6 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 9) AND (r1c4 = 3) AND (r1c6 = 5) AND (r1c7 = 7) AND (r2c2 = 3) AND (r2c4 = 8) AND (r2c9 = 2) AND (r3c3 = 8) AND (r3c5 = 2) AND (r3c7 = 6) AND (r4c3 = 2) AND (r4c8 = 9) AND (r4c9 = 7) AND (r5c2 = 7) AND (r5c3 = 6) AND (r5c5 = 5) AND (r5c7 = 1) AND (r6c2 = 8) AND (r6c7 = 3) AND (r7c4 = 9) AND (r7c9 = 1) AND (r8c6 = 1) AND (r9c8 = 6); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 1) AND (r1c6 = 6) AND (r1c9 = 7) AND (r2c2 = 2) AND (r2c4 = 5) AND (r2c7 = 8) AND (r3c3 = 9) AND (r3c4 = 7) AND (r3c9 = 6) AND (r4c1 = 7) AND (r4c3 = 5) AND (r5c3 = 1) AND (r5c5 = 3) AND (r5c7 = 2) AND (r5c8 = 9) AND (r7c5 = 9) AND (r7c6 = 5) AND (r8c1 = 2) AND (r8c9 = 3) AND (r9c1 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 2) AND (r1c2 = 9) AND (r1c4 = 1) AND (r1c5 = 4) AND (r2c5 = 5) AND (r2c6 = 8) AND (r3c1 = 1) AND (r3c2 = 8) AND (r3c5 = 6) AND (r3c7 = 5) AND (r4c1 = 8) AND (r4c9 = 2) AND (r5c2 = 1) AND (r5c4 = 7) AND (r5c9 = 6) AND (r6c7 = 7) AND (r6c8 = 9) AND (r7c1 = 4) AND (r7c7 = 2) AND (r7c8 = 1) AND (r8c9 = 9) AND (r9c1 = 7) AND (r9c4 = 2) AND (r9c7 = 4) AND (r9c9 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 6) AND (r1c3 = 1) AND (r1c5 = 9) AND (r3c1 = 9) AND (r3c3 = 7) AND (r3c5 = 4) AND (r3c8 = 6) AND (r4c3 = 8) AND (r4c8 = 4) AND (r5c1 = 7) AND (r5c2 = 3) AND (r5c3 = 2) AND (r5c8 = 9) AND (r6c1 = 1) AND (r6c8 = 7) AND (r7c2 = 8) AND (r7c3 = 4) AND (r7c4 = 6) AND (r7c5 = 1) AND (r7c9 = 9) AND (r8c1 = 2) AND (r8c3 = 9) AND (r8c5 = 8) AND (r8c6 = 4) AND (r8c7 = 3) AND (r9c5 = 2) AND (r9c6 = 7) AND (r9c8 = 8) AND (r9c9 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 4) AND (r1c6 = 1) AND (r1c8 = 2) AND (r2c8 = 3) AND (r2c9 = 4) AND (r3c3 = 5) AND (r3c5 = 6) AND (r4c4 = 3) AND (r4c9 = 7) AND (r5c3 = 1) AND (r5c7 = 6) AND (r6c1 = 6) AND (r6c6 = 2) AND (r7c5 = 4) AND (r7c7 = 1) AND (r8c1 = 9) AND (r8c2 = 7) AND (r9c2 = 3) AND (r9c4 = 5); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 8) AND (r1c2 = 9) AND (r2c1 = 3) AND (r2c3 = 6) AND (r2c5 = 4) AND (r3c2 = 1) AND (r3c3 = 4) AND (r4c2 = 7) AND (r4c9 = 1) AND (r5c3 = 1) AND (r5c5 = 6) AND (r6c1 = 2) AND (r6c6 = 7) AND (r6c7 = 9) AND (r6c9 = 8) AND (r7c1 = 7) AND (r7c4 = 6) AND (r7c5 = 2) AND (r7c6 = 1) AND (r7c7 = 8) AND (r7c9 = 3) AND (r8c4 = 7) AND (r8c6 = 3) AND (r8c7 = 4) AND (r8c8 = 9) AND (r9c2 = 3) AND (r9c5 = 8) AND (r9c6 = 9) AND (r9c8 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 4) AND (r2c2 = 4) AND (r2c5 = 7) AND (r2c8 = 3) AND (r2c9 = 6) AND (r3c1 = 2) AND (r3c5 = 3) AND (r3c6 = 6) AND (r3c8 = 8) AND (r4c4 = 1) AND (r4c5 = 4) AND (r4c9 = 7) AND (r5c1 = 1) AND (r5c6 = 3) AND (r5c8 = 6) AND (r6c4 = 6) AND (r6c8 = 2) AND (r7c1 = 3) AND (r7c5 = 5) AND (r7c8 = 1) AND (r8c2 = 5) AND (r8c4 = 7) AND (r8c5 = 8) AND (r8c6 = 2) AND (r9c9 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 8) AND (r1c8 = 1) AND (r2c6 = 2) AND (r2c8 = 3) AND (r2c9 = 4) AND (r3c3 = 5) AND (r3c5 = 6) AND (r4c4 = 4) AND (r4c8 = 7) AND (r5c3 = 2) AND (r5c7 = 6) AND (r6c2 = 1) AND (r6c6 = 5) AND (r7c5 = 8) AND (r7c7 = 2) AND (r8c1 = 7) AND (r8c2 = 3) AND (r8c4 = 1) AND (r9c2 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 8) AND (r1c4 = 4) AND (r1c5 = 3) AND (r1c7 = 9) AND (r1c8 = 1) AND (r2c1 = 3) AND (r2c5 = 9) AND (r3c2 = 4) AND (r3c4 = 7) AND (r3c6 = 1) AND (r3c9 = 6) AND (r4c2 = 7) AND (r4c4 = 1) AND (r4c5 = 4) AND (r4c7 = 5) AND (r5c1 = 6) AND (r5c3 = 3) AND (r6c1 = 5) AND (r6c2 = 1) AND (r6c8 = 8) AND (r7c1 = 7) AND (r7c3 = 6) AND (r7c4 = 8) AND (r7c8 = 9) AND (r8c2 = 3) AND (r8c4 = 9) AND (r9c2 = 9) AND (r9c4 = 3) AND (r9c9 = 8); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 7) AND (r1c3 = 1) AND (r1c4 = 2) AND (r1c5 = 5) AND (r1c8 = 8) AND (r2c1 = 8) AND (r2c3 = 6) AND (r2c5 = 7) AND (r2c6 = 4) AND (r2c9 = 5) AND (r3c2 = 9) AND (r3c3 = 4) AND (r3c6 = 6) AND (r3c7 = 7) AND (r5c3 = 8) AND (r5c4 = 6) AND (r5c6 = 5) AND (r5c9 = 9) AND (r6c4 = 8) AND (r6c5 = 2) AND (r6c6 = 1) AND (r6c8 = 4) AND (r6c9 = 6) AND (r7c1 = 6) AND (r7c6 = 8) AND (r7c9 = 1) AND (r8c1 = 1) AND (r8c3 = 9) AND (r8c9 = 7) AND (r9c2 = 4); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 1) AND (r1c5 = 5) AND (r1c7 = 6) AND (r2c1 = 8) AND (r2c3 = 7) AND (r3c1 = 3) AND (r4c4 = 7) AND (r4c6 = 8) AND (r4c8 = 3) AND (r5c2 = 1) AND (r5c7 = 4) AND (r7c2 = 4) AND (r7c5 = 6) AND (r7c7 = 2) AND (r8c1 = 5) AND (r8c8 = 8) AND (r9c4 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 7) AND (r1c5 = 9) AND (r1c7 = 2) AND (r2c3 = 6) AND (r2c7 = 3) AND (r2c9 = 8) AND (r3c2 = 5) AND (r3c5 = 8) AND (r3c6 = 3) AND (r3c8 = 7) AND (r3c9 = 9) AND (r4c3 = 4) AND (r4c4 = 3) AND (r4c7 = 7) AND (r4c8 = 6) AND (r5c7 = 8) AND (r5c9 = 2) AND (r6c1 = 5) AND (r6c2 = 6) AND (r8c2 = 8) AND (r8c3 = 9) AND (r8c4 = 5) AND (r8c6 = 6) AND (r9c1 = 3) AND (r9c2 = 2) AND (r9c9 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c3 = 2) AND (r1c4 = 8) AND (r1c6 = 1) AND (r1c7 = 5) AND (r1c8 = 4) AND (r2c5 = 3) AND (r3c4 = 4) AND (r3c5 = 6) AND (r3c6 = 5) AND (r4c1 = 8) AND (r4c3 = 3) AND (r4c6 = 9) AND (r4c7 = 4) AND (r4c9 = 5) AND (r5c2 = 5) AND (r5c6 = 3) AND (r5c9 = 1) AND (r6c3 = 6) AND (r6c7 = 3) AND (r7c4 = 2) AND (r7c6 = 4) AND (r8c3 = 5) AND (r8c5 = 1) AND (r8c6 = 8) AND (r8c7 = 6) AND (r8c8 = 2) AND (r9c3 = 9) AND (r9c5 = 5); SELECT * FROM sudoku_memory_combined_view WHERE (r1c4 = 1) AND (r2c1 = 1) AND (r2c2 = 2) AND (r2c5 = 9) AND (r2c8 = 7) AND (r3c5 = 7) AND (r3c6 = 6) AND (r5c2 = 6) AND (r5c5 = 3) AND (r5c6 = 9) AND (r5c8 = 1) AND (r6c1 = 5) AND (r6c3 = 9) AND (r6c4 = 4) AND (r6c6 = 7) AND (r6c8 = 2) AND (r7c3 = 2) AND (r7c6 = 3) AND (r7c7 = 4) AND (r7c8 = 5) AND (r8c1 = 6) AND (r8c4 = 7) AND (r8c5 = 2) AND (r8c8 = 3) AND (r8c9 = 9) AND (r9c2 = 7) AND (r9c4 = 9) AND (r9c5 = 4) AND (r9c6 = 1) AND (r9c8 = 6) AND (r9c9 = 2); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 2) AND (r2c3 = 5) AND (r2c5 = 3) AND (r2c6 = 9) AND (r2c7 = 8) AND (r3c1 = 8) AND (r3c2 = 4) AND (r3c3 = 9) AND (r3c5 = 7) AND (r4c3 = 7) AND (r4c4 = 3) AND (r4c5 = 2) AND (r4c6 = 6) AND (r5c4 = 7) AND (r5c5 = 4) AND (r5c6 = 8) AND (r5c9 = 3) AND (r6c6 = 5) AND (r7c3 = 3) AND (r7c5 = 6) AND (r7c9 = 5) AND (r8c2 = 5) AND (r8c4 = 9) AND (r8c8 = 6) AND (r9c1 = 4) AND (r9c3 = 8) AND (r9c5 = 5) AND (r9c6 = 7) AND (r9c8 = 3) AND (r9c9 = 9); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 1) AND (r1c2 = 9) AND (r2c1 = 8) AND (r2c5 = 7) AND (r2c8 = 1) AND (r2c9 = 6) AND (r3c2 = 7) AND (r3c4 = 2) AND (r3c7 = 5) AND (r3c9 = 3) AND (r4c8 = 2) AND (r4c9 = 7) AND (r5c2 = 3) AND (r5c9 = 8) AND (r6c1 = 9) AND (r6c3 = 5) AND (r7c2 = 1) AND (r7c3 = 8) AND (r7c6 = 2) AND (r7c8 = 3) AND (r8c9 = 2) AND (r9c2 = 6) AND (r9c5 = 1) AND (r9c8 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c1 = 8) AND (r1c3 = 5) AND (r1c9 = 2) AND (r2c4 = 9) AND (r2c6 = 1) AND (r3c1 = 3) AND (r4c2 = 6) AND (r4c4 = 7) AND (r4c7 = 4) AND (r5c1 = 2) AND (r5c5 = 5) AND (r6c8 = 6) AND (r7c4 = 3) AND (r7c5 = 8) AND (r8c2 = 1) AND (r8c7 = 9) AND (r9c2 = 4) AND (r9c8 = 7); SELECT * FROM sudoku_memory_combined_view WHERE (r1c2 = 8) AND (r2c1 = 1) AND (r2c3 = 7) AND (r2c7 = 8) AND (r2c9 = 3) AND (r3c6 = 6) AND (r3c9 = 1) AND (r4c2 = 2) AND (r5c1 = 3) AND (r5c5 = 1) AND (r6c3 = 8) AND (r6c4 = 5) AND (r6c7 = 6) AND (r6c8 = 9) AND (r7c5 = 3) AND (r7c6 = 7) AND (r7c7 = 9) AND (r8c6 = 1) AND (r9c1 = 5) AND (r9c2 = 9); UPDATE tests SET fin = NOW() WHERE fin IS NULL; SELECT TO_SECONDS(fin) - TO_SECONDS(debut) FROM tests;

**6. Gosser à la main!**

Maintenant que nous avons un échantillon représentatif et significatif et tout ce qu’il nous faut pour mesurer, de façon répétable et facile, chacun des changements que nous voulons effectuer, nous sommes en mesure de vérifier l’impact de 2 variables importantes : *optimizer_search_depth* et *join_buffer_size*.

Tout d’abord, la variable *optimizer_search_depth* dont voici les différents résultats :

Il est clair que cette variable a un impact majeur. Nous savons maintenant que la valeur optimale de cette variable (dans notre cas précis) est 1.

On serait tenté de croire que la variable *join_buffer_size* pourrait avoir un impact non négligeable mais ce n’est pas le cas ici.

Les différences de temps (hormis pour la valeur 2Mb) ne sont pas assez significatives pour indiquer une tendance. Malgré tout, **théoriquement**, cette variable devrait avoir un impact. Pour les biens de la cause, autant avoir plus de mémoire que moins pour cette variable! Je vous recommande donc 128Mb (plus, dans notre cas, serait un gaspillage de mémoire).

Finalement, pour mettre en valeur la différence entre une solution utilisant une table sur disque versus notre solution finale (une table en mémoire), l’histogramme suivant parle de lui-même!

Voilà! CQFD. En espérant que cette série d’articles vous aura permis de constater que parfois, il est nécessaire de penser *out of the box* et d’envisager des solutions saugrenues pour arriver à ses fins.

**7. Ressources et outils
**

Quelques-unes des ressources et des outils utilisés dans le cadre de cette série d’articles:

setbb.com : des forums de discussion sur le sudoku (en anglais) pour les programmeurs

enjoysudoku.com : des forums de discussions (en anglais) variés et nombreux sur les sudokus

QQWing : un outil (en ligne de commande) permettant de solutionner et de générer des grilles de sudoku

SudoCue : une application permettant de solutionner et générer des sudokus

Sudoku Explainer : une application permettant de solutionner et générer des sudokus

R : langage de programmation et environnement mathématique utilisé pour le traitement de données et l’analyse statistique

db4free.net : un serveur MySQL vous permettant de créer une base de donnée gratuitement et d’expérimenter

Pharo : un environnement de développement Smalltalk