QUERY PLAN
GroupAggregate (cost=54.13..54.22 rows=5 width=12)
Group Key: parent_id
-> Sort (cost=54.13..54.14 rows=6 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..54.05 rows=6 width=4)
Filter: (parent_id = ANY ('{1700,1709,1708,1703,1698,1620}'::integer[]))