Hi,
I’m using postgres 7.4.
I have two queries:
(1)
SELECT a,b
FROM table1
WHERE a=99
(2)
SELECT a,b,sum (o) as sum_o
FROM table2
GROUP BY a,b
Both Runs very fast.
But when I try to make (2) as a subquery of (1):
SELECT a,b,sum_o
FROM table1
LEFT JOIN (
SELECT a,b,sum (o) as sum_o
FROM table2
GROUP BY a,b
) sub_query
USING (a,b)
WHERE a=99
It runs 100 times slower.
I guess it has to do with the postgres unable to pass the a=99 inside the subquery
Any ideas ?
ishay
