Andreas Joseph Krogh <[EMAIL PROTECTED]> writes:
> Any idea why this works:
> SELECT distinct(g.groupname), g.id, g.p_id FROM onp_group g, onp_group g2
> WHERE g.id IN(SELECT g2.id UNION SELECT group_id FROM onp_group_children
> WHERE
> child_id = g2.id)
> AND g2.id IN(1,2,109,105, 112);
> And not this:
> SELECT g.id, g.p_id, distinct(g.groupname) FROM onp_group g, onp_group g2
> WHERE g.id IN(SELECT g2.id UNION SELECT group_id FROM onp_group_children
> WHERE
> child_id = g2.id)
> AND g2.id IN(1,2,109,105, 112);
DISTINCT is not a function, it's a modifier attached to SELECT. The
parentheses in your first example are a no-op.
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
