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Re: Joins within a table

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Steve Lefevre <lefevre(dot)10(at)osu(dot)edu>
Cc: pgsql-novice(at)postgresql(dot)org
Subject: Re: Joins within a table
Date: 2007-06-13 00:51:09
Message-ID: 28878.1181695869@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-novice
Steve Lefevre <lefevre(dot)10(at)osu(dot)edu> writes:
> I'm trying to do a JOIN within a table. In MySQL, I would do

> SELECT  main_table.field, join_table.field
> FROM main_table
> LEFT JOIN main_table AS join_table ON join_table.id = main_table.parent_id

Yeah, that's the same way you'd do a self-join in Postgres.

> However, in the Postgres documentation, I don't see anything on JOIN AS. 

Where did you look?  Maybe you are confusing the alias clause with the
join clause --- they are two different constructs.

			regards, tom lane

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