QUERY PLAN
GroupAggregate (cost=52.64..52.80 rows=8 width=12)
Group Key: parent_id
-> Sort (cost=52.64..52.67 rows=10 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..52.48 rows=10 width=4)
Filter: (parent_id = ANY ('{1596,1734,1747,1746,1727}'::integer[]))