QUERY PLAN
GroupAggregate (cost=48.95..49.02 rows=4 width=12)
Group Key: parent_id
-> Sort (cost=48.95..48.96 rows=4 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..48.91 rows=4 width=4)
Filter: (parent_id = ANY ('{1596,1641,1630,1629}'::integer[]))