From: Josh Berkus <josh@agliodbs.com>
To: Adam Sherman <adam@tritus.ca>
To: pgsql-sql@postgresql.org
Subject: Re: Locating all Children given Set of Parents
Date: Tue, 13 May 2003 09:47:46 -0700
Message-ID: <200305130947.46844.josh@agliodbs.com> (raw)
In-Reply-To: <184690000.1052842782@saturn>
References: <184690000.1052842782@saturn>
Adam,
> I have three tables: parents, children & parent_child_mm.
>
> (So Parents and Children are in a Many-to-Many relationship.)
>
> Given a set of Parents, say 1, 2 & 3, how do I retrieve all children in an
> efficient manner? (I want each child to appear only once.)
Easy:
Select children.*
from children where exists (select pc_id
from parent_child
where pc.child_id = children.id
and pc.parent_id IN ($parent_id_list)
);
--
Josh Berkus
Aglio Database Solutions
San Francisco
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To: pgsql-sql@postgresql.org
Cc: josh@agliodbs.com, adam@tritus.ca
Subject: Re: Locating all Children given Set of Parents
In-Reply-To: <200305130947.46844.josh@agliodbs.com>
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