QUERY PLAN
GroupAggregate (cost=147.02..147.08 rows=3 width=12)
Group Key: parent_id
-> Sort (cost=147.02..147.03 rows=3 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..147.00 rows=3 width=4)
Filter: (parent_id = ANY ('{1600,1598}'::integer[]))