QUERY PLAN
GroupAggregate (cost=52.52..52.63 rows=6 width=12)
Group Key: parent_id
-> Sort (cost=52.52..52.54 rows=7 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..52.42 rows=7 width=4)
Filter: (parent_id = ANY ('{1535,1672,1669,1667,1662,1661}'::integer[]))