QUERY PLAN
GroupAggregate (cost=174.03..174.28 rows=8 width=12)
Group Key: parent_id
-> Sort (cost=174.03..174.09 rows=23 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..173.51 rows=23 width=4)
Filter: (parent_id = ANY ('{1605,1604,1603,1600,1598,1595,1592,1591,1586,1585,1584,1583,1582,1575,1568,1567,1566,1564,1563,1562}'::integer[]))