QUERY PLAN
GroupAggregate (cost=46.65..46.70 rows=3 width=12)
Group Key: parent_id
-> Sort (cost=46.65..46.66 rows=3 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..46.62 rows=3 width=4)
Filter: (parent_id = ANY ('{1535,1667}'::integer[]))