QUERY PLAN
GroupAggregate (cost=158.85..158.99 rows=6 width=12)
Group Key: parent_id
-> Sort (cost=158.85..158.88 rows=10 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..158.69 rows=10 width=4)
Filter: (parent_id = ANY ('{1603,1600,1598,1595,1592,1591,1583,1537,1536,1535}'::integer[]))