"Jan Mate" <mate@yeea.eu> writes:
> Comparison between null and timestamp null value is not correct.
No, it's your expectations that are not correct. Null is not "equal to"
null --- in fact both the queries you show will evaluate the WHERE
clause as null (unknown).
> Is there any other way to compare the subquery result (using IN or NOT IN)
> with null value?
Don't try to use null as a normal data value. Sooner or later you'll
always regret it.
regards, tom lane
