-----Original Message----- From: sqlite-users-boun...@sqlite.org [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Andrey Fedorov Sent: Tuesday, April 21, 2009 1:27 PM To: sqlite-users@sqlite.org Subject: [sqlite] Difference between all the joins
Hi all, According to the join-op syntax [1], SQLite has 13 distinct join statements: , JOIN LEFT JOIN OUTER JOIN LEFT OUTER JOIN INNER JOIN CROSS JOIN NATURAL JOIN NATURAL LEFT JOIN NATURAL OUTER JOIN NATURAL LEFT OUTER JOIN NATURAL INNER JOIN NATURAL CROSS JOIN Are they all unique? Which are equivalent? - Andrey 1. http://sqlite.org/syntaxdiagrams.html#join-op _______________________________________________ _______________________________________________ _______________________________________________ Hello, Andrey, No, many are synonyms included (I think) as part of the SQL standards or to ease conversion from various other SQL dialects. E.g. an "unadorned" JOIN is identical to an INNER JOIN. Inner joins have no "left" or "right" so a LEFT JOIN can be used as a synonym for a LEFT OUTER JOIN. Furthermore, LEFT is a default for OUTER JOINS, so OUTER JOIN == LEFT JOIN == LEFT OUTER JOIN. This article looks interesting: http://en.wikipedia.org/wiki/Join_(SQL) _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
