QUERY PLAN
GroupAggregate (cost=49.84..50.11 rows=13 width=12)
Group Key: parent_id
-> Sort (cost=49.84..49.89 rows=18 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..49.47 rows=18 width=4)
Filter: (parent_id = ANY ('{1596,1641,1647,1696}'::integer[]))