Re: group by error message?

On Thu, Sep 25, 2008 at 11:01:08AM -0400, Tom Lane wrote:
> Louis-David Mitterrand <vindex+lists-pgsql-general(at)apartia(dot)org> writes:
> > critik=# select distinct pt.type_fr,sum(e2.id_event) from person_type pt natural join person_to_event join event e using (id_event) LEFT JOIN event e2 ON e.id_event = e2.id_event AND e2.id_event=219 join event_type et ON e.id_event_type = et.id_event_type where et.type_fr='théâtre' GROUP BY pt.type_fr IS NULL;
>
> > gives this error:
>
> > ERROR: column "pt.type_fr" must appear in the GROUP BY clause or be used in an aggregate function
>
> > But pt.type_fr is _already_ in the group by.
>
> No, "pt.type_fr IS NULL" is in the group by. That doesn't ensure that
> each group has a unique value of pt.type_fr itself.

Oops, once more I jumped the gun a bit too fast. Thanks for catching it
Tom!

Best regards,