From: Aarni =?iso-8859-1?q?Ruuhim=E4ki?= <aarni@kymi.com>
Reply-To: aarni@kymi.com
Organization: KYMI.com
To: Richard Huxton <dev@archonet.com>
Subject: Re: Originally created and last_mod by whom and when ?
Date: Wed, 14 Nov 2007 14:39:13 +0200
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 <473ADBF7.1060908@archonet.com>
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Cc: pgsql-sql@postgresql.org
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On Wednesday 14 November 2007 13:28, Richard Huxton wrote:
> Aarni Ruuhim=E4ki wrote:
> > Hello,
> >
> > In a web app (Pg 8.2.4 + php) I have product and other tables with fiel=
ds
> > like
> >
> > product_created timestamp without time zone
> > product_created_user_id integer
> > product_last_mod timestamp without time zone
> > product_last_mod_user_id integer
> >
> > The person who last modified an item can obviously be someone else who
> > originally created it.
> >
> > I can get the names and timestamps with two separate queries but how can
> > I do a single query to get the names of both ?
>
> Alias the tables, so you can join to the user-table twice.
>
> SELECT p.*, u_cre.username as created_by, u_mod.username as modified_by
> FROM
>    products p
> LEFT JOIN
>    app_users u_cre ON p.product_created_user_id =3D u_cre.id
> LEFT JOIN
>    app_users u_mod ON p.product_last_mod_user_id =3D u.mod.id
> ;

Charming ! Many thanks to you Richard.

Aarni
=2D-=20