Re: select where id=random()*something returns two results

Ulrich Meis <u.meis@gmx.de>

From: Ulrich Meis <u.meis@gmx.de>
To:
Cc: pgsql-bugs@postgresql.org
Date: 2003-09-21T12:21:20Z
Lists: pgsql-bugs
> -----Original Message-----
> From: pgsql-bugs-owner@postgresql.org [mailto:pgsql-bugs-
> owner@postgresql.org] On Behalf Of Jean-Luc Lachance
> Sent: Friday, September 19, 2003 4:44 PM
> To: Rod Taylor
> Cc: Ulrich Meis; pgsql-bugs@postgresql.org
> Subject: Re: [BUGS] select where id=random()*something returns two
results
> 
> Rod,
> 
> If the table has 100,000 tupples your query is generating 100,000 new
> tupples...
> Try:
> 
> select * from quotes where id = (
>   select int8( 1 + random() * (
>     select id from quotes order by id desc limit 1)));
> 

How about

select * from quotes where id=1+int8((select random())*(select max(id)
from quotes));

It works, but is it more or less efficient?