From: | Marti Raudsepp <marti(at)juffo(dot)org> |
---|---|
To: | David W Noon <dwnoon(at)ntlworld(dot)com> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Set returning functions in select column list |
Date: | 2012-02-17 16:21:07 |
Message-ID: | CABRT9RAMwmvNruvqe4HrvUZUMCMDLhDofjHh50O-w98kjcub7A@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
On Fri, Feb 17, 2012 at 17:31, David W Noon <dwnoon(at)ntlworld(dot)com> wrote:
> The words to search for are "Cartesian product". This is the way
> RDBMSes have handled unconstrained implicit joins since the days of
> SQL/DS.
Yeah, that's what Jack was confused about -- it's actually *not* a
cartesian product. It simply stops enumerating when all the SRFs reach
the end at the same time.
Both of these queries generate 6 rows, although a cartesian product
would mean 12 in the second query:
select generate_series(1,2), generate_series(1,3);
select generate_series(1,2), generate_series(1,6);
Regards,
Marti
From | Date | Subject | |
---|---|---|---|
Next Message | Marti Raudsepp | 2012-02-17 16:22:34 | Re: MySQL search query is not executing in Postgres DB |
Previous Message | Scott Marlowe | 2012-02-17 16:19:06 | Re: MySQL search query is not executing in Postgres DB |