QUERY PLAN
GroupAggregate (cost=54.90..55.02 rows=6 width=12)
Group Key: parent_id
-> Sort (cost=54.90..54.92 rows=8 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..54.78 rows=8 width=4)
Filter: (parent_id = ANY ('{1668,1669,1667,1671,1670,1664,1658,1666}'::integer[]))