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
justGOSUB without RETURN.
