Re: [SQL] SubSelect as a column

Tom Lane wrote:

> Lars <lars@sscsinc.com> writes:
> > I am trying to use a subselect as a column name, but it appears as if this
> > is not supported in Postgresql. Here is the query:
>
> > SELECT u.idnum, u.username,
> >   (SELECT COUNT(t.techid)
> >    FROM ticket t
> >    WHERE t.techid = u.idnum)
> > FROM users u;
>
> Nope, doesn't work in 6.5.*.  It is there in current sources for the
> upcoming 7.0 release.  Can't think of any good workaround in 6.5...
>
>                         regards, tom lane
>
> ************

i would do an UNION  of the tuples coming from the joint
with the tuples from "users" who don't have a counterpart in "ticket",
using "not exists" and adding to them a zero count.
Hoping it will help
regards
P.Jacquot