Re: self-join on subselect

From: "Jim C(dot) Nasby" <decibel(at)decibel(dot)org>
To: PFC <lists(at)boutiquenumerique(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: self-join on subselect
Date: 2005-01-27 01:24:36
Message-ID: 20050127012436.GL67721@decibel.org
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It's not at all clear what you're asking. Do you have a real example,
preferably with EXPLAIN output?

On Wed, Jan 26, 2005 at 11:12:25PM +0100, PFC wrote:
>
> How do you do a self-join on a subselect ?
>
> like
> SELECT a.x+b.x FROM (subselect) a, (subselect) b WHERE a.id = b.id+10
>
> but without performing the subselect twice
> ..................................?
>
> ---------------------------(end of broadcast)---------------------------
> TIP 9: the planner will ignore your desire to choose an index scan if your
> joining column's datatypes do not match
>

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Jim C. Nasby, Database Consultant decibel(at)decibel(dot)org
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