QUERY PLAN
GroupAggregate (cost=50.64..50.73 rows=5 width=12)
Group Key: parent_id
-> Sort (cost=50.64..50.66 rows=5 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..50.59 rows=5 width=4)
Filter: (parent_id = ANY ('{1596,1734,1768,1769}'::integer[]))