Re: right join problem

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)