QUERY PLAN
GroupAggregate (cost=162.24..162.42 rows=8 width=12)
Group Key: parent_id
-> Sort (cost=162.24..162.27 rows=13 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..162.00 rows=13 width=4)
Filter: (parent_id = ANY ('{1618,1617,1616,1615,1600,1598,1592,1591,1583,1537,1536,1535}'::integer[]))