If the aim is purely to find the progs without events, it might be more efficient to use something like
select * from progs where not exist (select id_prog from events where id_prog = progs.id_prog); My syntax might be off, check "not exists" documentation for more info. On Tue, Dec 15, 2009 at 8:14 PM, Gavin Towey <gto...@ffn.com> wrote: > Hi Miguel, > > You'll need to use LEFT JOIN, that will show all records that match and a > row in the second table will all values NULL where there is no match. Then > you find all those rows that have no match in your WHERE clause. > > Regards, > Gavin Towey > > -----Original Message----- > From: Miguel Vaz [mailto:pagong...@gmail.com] > Sent: Tuesday, December 15, 2009 10:43 AM > To: mysql@lists.mysql.com > Subject: Count records in join > > Hi, > > I am stuck with a suposedly simple query: > > - i have two tables (: > > PROGS > id_prog > name > > EVENTS > id > id_prog > name > > How can i list all records from PROGS with a sum of how many events each > have? I want to find the progs that are empty. > > I remember something about using NULL, but i cant remember. :-P > > Thanks. > > MV > > This message contains confidential information and is intended only for the > individual named. If you are not the named addressee, you are notified that > reviewing, disseminating, disclosing, copying or distributing this e-mail is > strictly prohibited. Please notify the sender immediately by e-mail if you > have received this e-mail by mistake and delete this e-mail from your > system. E-mail transmission cannot be guaranteed to be secure or error-free > as information could be intercepted, corrupted, lost, destroyed, arrive late > or incomplete, or contain viruses. The sender therefore does not accept > liability for any loss or damage caused by viruses or errors or omissions in > the contents of this message, which arise as a result of e-mail > transmission. [FriendFinder Networks, Inc., 220 Humbolt court, Sunnyvale, CA > 94089, USA, FriendFinder.com > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/mysql?unsub=vegiv...@tuxera.be > >
