Alan Nilsson <anilsson@apple.com> writes:
> Could someone explain to me what I'm missing here.
Probably there are some NULLs in dasp.asp_id. NOT IN cannot succeed
when there are any nulls in the sub-select result: per SQL spec, the
outcome of such a test can only be FALSE or NULL. If that isn't the
behavior you want, try recasting the query to use NOT EXISTS.
regards, tom lane