QUERY PLAN
GroupAggregate (cost=50.07..50.32 rows=13 width=12)
Group Key: parent_id
-> Sort (cost=50.07..50.11 rows=16 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..49.75 rows=16 width=4)
Filter: (parent_id = ANY ('{1596,1647,1727,1724}'::integer[]))