QUERY PLAN
GroupAggregate (cost=51.89..51.98 rows=5 width=12)
Group Key: parent_id
-> Sort (cost=51.89..51.90 rows=6 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..51.81 rows=6 width=4)
Filter: (parent_id = ANY ('{1667,1669,1668,1664,1658,1666}'::integer[]))