QUERY PLAN
GroupAggregate (cost=48.93..49.05 rows=6 width=12)
Group Key: parent_id
-> Sort (cost=48.93..48.95 rows=7 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..48.84 rows=7 width=4)
Filter: (parent_id = ANY ('{1596,1641,1647,1658}'::integer[]))