QUERY PLAN
GroupAggregate (cost=151.33..151.41 rows=4 width=12)
Group Key: parent_id
-> Sort (cost=151.33..151.34 rows=5 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..151.27 rows=5 width=4)
Filter: (parent_id = ANY ('{1545,1547,1546,1548,1549}'::integer[]))