QUERY PLAN
GroupAggregate (cost=50.38..50.46 rows=4 width=12)
Group Key: parent_id
-> Sort (cost=50.38..50.39 rows=5 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..50.32 rows=5 width=4)
Filter: (parent_id = ANY ('{1658,1664,1666,1667,1668}'::integer[]))