QUERY PLAN
GroupAggregate (cost=49.52..49.59 rows=4 width=12)
Group Key: parent_id
-> Sort (cost=49.52..49.53 rows=4 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..49.48 rows=4 width=4)
Filter: (parent_id = ANY ('{1535,1672,1667}'::integer[]))