| From: | Michael Fuhr <mike(at)fuhr(dot)org> |
|---|---|
| To: | Benjamin Smith <lists(at)benjamindsmith(dot)com> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Dumb question about count() |
| Date: | 2005-07-22 05:35:08 |
| Message-ID: | 20050722053507.GA13925@winnie.fuhr.org |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
On Thu, Jul 21, 2005 at 10:09:07PM -0700, Benjamin Smith wrote:
> select classroom.title,
> count(students.id) AS students,
> count(seats.id) AS seats
> from classrooms, students, seats
> where classrooms.id=students.classrooms_id
> and classrooms.id=seats.id
>
> Except that it counts 0s for seats/students.
>
> Why can't I recall/find how to do this particular join?
Sounds like you're looking for an outer join.
http://www.postgresql.org/docs/8.0/static/tutorial-join.html
http://www.postgresql.org/docs/8.0/static/queries-table-expressions.html#QUERIES-FROM
--
Michael Fuhr
http://www.fuhr.org/~mfuhr/
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Rose, Juergen | 2005-07-22 07:10:01 | Re: Insert into ... Select ... From ... too intelligent transaction |
| Previous Message | Bruce Momjian | 2005-07-22 05:14:44 | Re: Strange input/cast semantics for inet |