Re: Originally created and last_mod by whom and when ?

On Wednesday 14 November 2007 13:28, Richard Huxton wrote:
> Aarni Ruuhimäki wrote:
> > Hello,
> >
> > In a web app (Pg 8.2.4 + php) I have product and other tables with fields
> > 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 = u_cre.id
> LEFT JOIN
> app_users u_mod ON p.product_last_mod_user_id = u.mod.id
> ;

Charming ! Many thanks to you Richard.

Aarni
--