QUERY PLAN
GroupAggregate (cost=46.31..46.35 rows=2 width=12)
Group Key: parent_id
-> Sort (cost=46.31..46.31 rows=2 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..46.30 rows=2 width=4)
Filter: (parent_id = ANY ('{1645,1620}'::integer[]))