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List:       postgresql-sql
Subject:    Re: [SQL] inner join is much faster! is that right?
From:       "James Im" <im-james () hotmail ! com>
Date:       2006-09-19 13:44:13
Message-ID: BAY7-F27352E5152460F67D8E96896220 () phx ! gbl
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I was doing the explain thing when I discovered my mistake!

The think is that I over simplyfied my examples. instead of searching
for one ID, I was searching for several ids and I forgot to put a
parentesis arround the or like this.

I was doing this:
select *
from file a, file_tag b, tag c
where a.id_file=b.id_file and b.id_tag=c.id_tag and
a.id_file=10000001000000 or a.id_file=10000001000200

But I should have done this:

select *
from file a, file_tag b, tag c
where a.id_file=b.id_file and b.id_tag=c.id_tag and
(a.id_file=10000001000000 or a.id_file=10000001000200)

This changes everything. The performance is now acceptable!

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