QUERY PLAN
GroupAggregate (cost=51.14..51.24 rows=5 width=12)
Group Key: parent_id
-> Sort (cost=51.14..51.16 rows=6 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..51.06 rows=6 width=4)
Filter: (parent_id = ANY ('{1713,1712,1711,1620}'::integer[]))