QUERY PLAN
GroupAggregate (cost=49.37..49.43 rows=4 width=12)
Group Key: parent_id
-> Sort (cost=49.37..49.38 rows=4 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..49.33 rows=4 width=4)
Filter: (parent_id = ANY ('{1535,1672,1667}'::integer[]))