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From: Richard Huxton <dev@archonet.com>
Organization: Archonet Ltd
To: Gary Stainburn <gary.stainburn@ringways.co.uk>,
	pgsql-sql@postgresql.org
Subject: Re: master-detail relationship and count
Date: Fri, 29 Nov 2002 10:35:12 +0000
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References: <200211291006.06749.gary.stainburn@ringways.co.uk>
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On Friday 29 Nov 2002 10:06 am, Gary Stainburn wrote:
> Hi folks.
>
> I've got a master detail relationship where I have a railway route table
> listing landmarks along the route,  and a Links table listing URL's
> associated with that landmark. Listed below:
>
> How can I do a query showing the landmark ID, the landmark name, and a
> count of links associated with that  landmark.  Below is a SQL statement
> that although is illegal, gives a good idea of what I'm looking for.
>
> select r.rtid, r.rtname, l.count(*) from route r, links l where l.lktype =
=3D
> 'R' and l.lklid =3D r.rtid;

You'll want to GROUP BY

SELECT r.rtid, r.rtname, l.count(*) FROM route r, links l WHERE l.lktype=3D=
'R'=20
AND l.lklid=3Dr.rtid GROUP BY r.rtid, r.rtname;


--=20
  Richard Huxton