does the order in where clauses matter?

[thoresson]

I just realized that the order in where clauses matters. Or at least seems to. These two sql statements does not retrieve the same result:

SELECT count(*) AS new FROM comments, user2album, album WHERE album.user_id = '2' AND comments.album_id = album.album_id AND comments.comment_date > '2004-11-28 12:06:06' AND user2album.user_id = '1' 

SELECT count(*) AS new FROM comments, user2album, album WHERE album.user_id = '1' AND comments.album_id = album.album_id AND user2album.user_id = '2' AND comments.comment_date > '2004-11-28 12:06:06' 

Why?

[r937]

they produce different results because they are different queries

query 1: album.user_id = '2' and user2album.user_id = '1'
query 2: album.user_id = '1' and user2album.user_id = '2'

different queries, different data, different results

[thoresson]

Thanks. Sometimes one doesn't see the most obvious. Thanks.