Is this a bug, or don't I understand coalesce()? create table test (a int, b int); insert into test values (1,null); insert into test values (2,1); insert into test values (2,2); select * from test; -- returns: select sum(b) from test where a=1; -- null select sum(b) from test where a=2; -- 3 select coalesce(0,sum(b)) from test where a=1; -- 0 select coalesce(0,sum(b)) from test where a=2; -- 0 delete from test where a=1; select coalesce(0,sum(b)) from test where a=2; -- 0 !
So when I use coalesce() with sum(), I always get the constant. I would have expected it only in the case where sum() returns null.. What am I missing? Cheers, Patrick (PostgreSQL 8.2devel of 21st November 2006) ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
