QUERY PLAN
GroupAggregate (cost=154.28..154.34 rows=3 width=12)
Group Key: parent_id
-> Sort (cost=154.28..154.29 rows=4 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..154.24 rows=4 width=4)
Filter: ((status = 1) AND (parent_id = ANY ('{1545,1547,1546,1548,1549}'::integer[])))