QUERY PLAN
GroupAggregate (cost=48.07..48.27 rows=10 width=12)
Group Key: parent_id
-> Sort (cost=48.07..48.10 rows=13 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..47.83 rows=13 width=4)
Filter: (parent_id = ANY ('{1596,1641,1647}'::integer[]))