QUERY PLAN
GroupAggregate (cost=59.29..59.46 rows=9 width=12)
Group Key: parent_id
-> Sort (cost=59.29..59.32 rows=10 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..59.12 rows=10 width=4)
Filter: (parent_id = ANY ('{60,61,62,63,64,65,66,67,68,69}'::integer[]))