Re: - Slow Query - Mailing list pgsql-performance

From Tom Lane
Subject Re: - Slow Query
Date
Msg-id 13880.1246470771@sss.pgh.pa.us
Whole thread Raw
In response to Re: - Slow Query  (Scott Marlowe <scott.marlowe@gmail.com>)
Responses Re: - Slow Query  (Scott Marlowe <scott.marlowe@gmail.com>)
List pgsql-performance
Scott Marlowe <scott.marlowe@gmail.com> writes:
> Sometimes putting a where clause portion into the on clause helps.
> like:
> select * from a left join b on (a.id=b.id) where a.somefield=2
> might run faster with
> select * from a left join b on (a.id=bid. and a.somefield=2);
> but it's hard to say.

Uh, those are not the same query ... they will give different results
for rows with a.somefield different from 2.

            regards, tom lane

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