QUERY PLAN
GroupAggregate (cost=60.47..60.64 rows=9 width=12)
Group Key: parent_id
-> Sort (cost=60.47..60.50 rows=10 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..60.30 rows=10 width=4)
Filter: (parent_id = ANY ('{70,71,72,73,74,75,76,77,78,79}'::integer[]))