In response to Greenhorn : > Hi, > > I'm trying to retrieve all meter_id from table meter, and for meter_id > without amount, I'd like it to show nothing, 'null'. I've used right > join here but it's not giving me my desired result. Is there another > way to do this? Here's the query I'm trying. > > Thanks in advance! > > select m.meter_id, mp.meter_id, sum(amount_in_cents) as am > from meter m > right join transaction_mpark mp on (m.meter_id = mp.meter_id) > where date_time between '2009-09-28 00:00:00' and '2009-10-04 23:59:59' > group by m.meter_id, mp.meter_id > order by m.meter_id
Use a left join instead? test=*# select * from master; id | name ----+---------- 1 | master 1 2 | master 2 (2 rows) test=*# select * from slave; id | value ----+------- 1 | 1 1 | 2 1 | 3 (3 rows) test=*# select m.id, s.id, sum(s.value) from master m right join slave s on (m.id=s.id) group by m.id, s.id; id | id | sum ----+----+----- 1 | 1 | 6 (1 row) test=*# select m.id, s.id, sum(s.value) from master m left join slave s on (m.id=s.id) group by m.id, s.id; id | id | sum ----+----+----- 1 | 1 | 6 2 | | (2 rows) Andreas -- Andreas Kretschmer Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header) -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
