RE: [HACKERS] Bug on complex subselect (was: Bug on complex join)

Oleg Broytmann <phd@sun.med.ru>

From: Oleg Broytmann <phd@sun.med.ru>
To: "Jackson, DeJuan" <djackson@cpsgroup.com>
Cc: PostgreSQL-development <pgsql-hackers@postgreSQL.org>
Date: 1999-03-11T12:48:12Z
Lists: pgsql-hackers
Hello!

   Vadim already gave the idea to use EXISTS. Will try it.
   Thanks to all who replied!

On Wed, 10 Mar 1999, Jackson, DeJuan wrote:
> Try your query this way:
>  SELECT DISTINCT subsec_id
>    FROM positions p
>   WHERE EXISTS(SELECT 1
>                  FROM central c, shops s, districts d
>                 WHERE p.pos_id = c.pos_id AND 
>                       c.shop_id = s.shop_id AND
>                       s.distr_id = d.distr_id AND
>                       d.city_id = 2);

> Make sure you have indexes on pos_id, shop_id, distr_id, and city_id.

   All these are primary keys in corresponding tables, and hence have
UNIQUE indicies. Is it enough?

Oleg.
---- 
    Oleg Broytmann     http://members.xoom.com/phd2/     phd2@earthling.net
           Programmers don't die, they just GOSUB without RETURN.