QUERY PLAN
GroupAggregate (cost=50.93..51.02 rows=5 width=12)
Group Key: parent_id
-> Sort (cost=50.93..50.94 rows=5 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..50.87 rows=5 width=4)
Filter: (parent_id = ANY ('{1535,1537,1667,1822}'::integer[]))