Re: Wierd query behaviour

"Josh Berkus" <josh(at)agliodbs(dot)com> writes:
> UPDATE cases SET status = 99
> WHERE status = 1 AND NOT EXISTS(
> SELECT case_id FROM case_clients
> WHERE date_resolved IS NULL OR
> date_resolved > ((current_date - "interval"('1 year'))::DATE)
> and case_clients.case_id = cases.case_id);

It says here that OR binds at lower priority than AND. Did you really
mean

... WHERE (date_resolved IS NULL OR
date_resolved > ((current_date - "interval"('1 year'))::DATE))
and case_clients.case_id = cases.case_id);

Since IS NULL isn't indexable, the first version cannot be indexscanned
at all. The second version gives you a shot at using the
case_clients.case_id index.

regards, tom lane