Hi, I found an interesting article which explains how to solve "sudoku" by using SQL(unfortunately written in Japanese): http://codezine.jp/article/detail/1629?p=2
In the article example sudoku is: http://static.shoeisha.jp/cz/static/images/article/1629/problem4.gif To solve the example you create following table: CREATE TABLE nums (n INT NOT NULL PRIMARY KEY); INSERT INTO nums VALUES (1); INSERT INTO nums VALUES (2); INSERT INTO nums VALUES (3); INSERT INTO nums VALUES (4); INSERT INTO nums VALUES (5); INSERT INTO nums VALUES (6); INSERT INTO nums VALUES (7); INSERT INTO nums VALUES (8); INSERT INTO nums VALUES (9); Then execute the huge SELECT: http://codezine.jp/static/images/article/1629/html/sql.html In the page first one takes infinite time by PostgreSQL 9.0.1. Next one can be executed very quickly because the join order is explicitely specified by cross join syntax. This seems to be a limitation of PostgreSQL optimizer and I would like it be removed. Comments? BTW according to the article, Oracle execute the first SELECT(the one PostgreSQL takes infinite time) in 10 seconds. It seems Oracle's optimizer is sperior in this regard. -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese: http://www.sraoss.co.jp -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
