| From: | Kris Jurka <books(at)ejurka(dot)com> |
|---|---|
| To: | Ulrich Meis <u(dot)meis(at)gmx(dot)de> |
| Cc: | <pgsql-bugs(at)postgresql(dot)org> |
| Subject: | Re: select where id=random()*something returns two results |
| Date: | 2003-09-19 01:15:21 |
| Message-ID: | Pine.LNX.4.33.0309182114020.26639-100000@leary.csoft.net |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-bugs |
On Fri, 19 Sep 2003, Ulrich Meis wrote:
> select * from quotes where id=1+round(random()* cast ((select max(id)
> from quotes) as double precision));
> id | quote |
> author
> -----+-----------------------------------------------------------+------
> -----------
> 187 | Vergib Deinen Feinden, aber vergiss niemals ihre Namen. | John
> F. Kennedy
> 377 | Die Wirklichkeit ist nicht so oder so, sondern so und so. | Harry
> Mulisch
> (2 rows)
>
> I'm not really into databases, but this sounds wrong. Most of the time,
> I actually get 0 results.
The problem is that random() is evaluated on each line giving a different
result.
Kris Jurka
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Rod Taylor | 2003-09-19 01:25:14 | Re: select where id=random()*something returns two results |
| Previous Message | Ulrich Meis | 2003-09-19 00:49:18 | select where id=random()*something returns two results |