Re: is this use of subquery "smart"

On Wed, Feb 4, 2009 at 4:33 PM, Chris <dmagick@gmail.com> wrote: > > > Solution 2: >> SELECT r.reg_id, r.date_registered, r.old_record, if(r.ghost_record!=0, >> (SELECT CONCAT(people.last_name, ', ', people.first_name) FROM people, >> registrants WHERE people.instance_id=12 and >> people.person_id=registrants.person_id AND >> registrants.reg_id=r.ghost_record), 'y') as registered_by_name >> FROM registrants r >> WHERE r.org_id=12 >> AND r.reg_status=0 >> AND r.reg_id=r.person_id >> >> this way subquery will be executed "everytime", but I have everything on >> one place? >> > > Because it has to evaluate the whole 'if' statement (including your > subquery) for each row in the result set. > > Best place to ask would be on the mysql mailing list: > > http://lists.mysql.com/ > > -- > Postgresql & php tutorials > http://www.designmagick.com/ > > > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php > > try a case when then statement. -- Bastien Cat, the other other white meat