QUERY PLAN
GroupAggregate (cost=54.51..54.82 rows=15 width=12)
Group Key: parent_id
-> Sort (cost=54.51..54.56 rows=21 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..54.05 rows=21 width=4)
Filter: (parent_id = ANY ('{1596,1641,1647,1697,1696,1687}'::integer[]))