From: Seb <spluque@gmail.com>
To: pgsql-sql@postgresql.org
Subject: Re: self join
Date: Sat, 14 May 2011 17:49:15 -0500
Message-ID: <87tycwsxsk.fsf@kolob.subpolar.dyndns.org> (raw)
References: <87y629rl34.fsf@kolob.subpolar.dyndns.org>
<BANLkTinOMHW_j0e6-6BHr4BOGLZKwEEZDA@mail.gmail.com>
On Sun, 15 May 2011 07:39:06 +0900,
Ian Lawrence Barwick <barwick@gmail.com> wrote:
[...]
> Your query doesn't have an explicit join and is producing a cartesian
> result.
> I don't think a self- join will work here; a subquery should produce
> the result you're after:
> SELECT * FROM tmp t1 WHERE NOT EXISTS(SELECT TRUE FROM tmp t2 WHERE
> t2.b=t1.a);
This produces exactly the result I'm after. I'll need to understand the
EXISTS statement there in more detail.
Thanks!
--
Seb
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To: pgsql-sql@postgresql.org
Cc: spluque@gmail.com
Subject: Re: self join
In-Reply-To: <87tycwsxsk.fsf@kolob.subpolar.dyndns.org>
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