QUERY PLAN
GroupAggregate (cost=53.08..53.21 rows=7 width=12)
Group Key: parent_id
-> Sort (cost=53.08..53.10 rows=8 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..52.96 rows=8 width=4)
Filter: (parent_id = ANY ('{1731,1713,1712,1711,1620}'::integer[]))