Re: update with multi table join

From: Michel Cadot <micadot2removethat_at_free.fr>
Date: Thu, 6 Nov 2003 23:05:08 +0100
Message-ID: <3faac572$0$256$636a55ce@news.free.fr>

"Ken Chesak" <datavector_at_hotmail.com> a écrit dans le message de news:3f2f39c4.0311061316.78f840b5_at_posting.google.com...
> When the subquery finds nothing the id_bjn is updated with null. How
> can I avoid updating records when there is no match is found in the
> subquery?
>
> update w_rg101 w
> set id_bjn = ( select c.id_destination from bjn a, bjn_destination c
> where w.id_region_tw = a.id_region
> and w.id_unit_tw = a.id_unit
> and w.id_mail_tw = a.id_mail)
> where cd_source <> 'ITSI' and id_bjn is null;

What about about adding "and exists '(the subquery)'"? BTW there is no join condition between bjn_destination and the other tables.

Michel Cadot Received on Thu Nov 06 2003 - 16:05:08 CST