QUERY PLAN
GroupAggregate (cost=48.13..48.17 rows=2 width=12)
Group Key: parent_id
-> Sort (cost=48.13..48.14 rows=2 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..48.12 rows=2 width=4)
Filter: (parent_id = ANY ('{1756,1757}'::integer[]))