QUERY PLAN
GroupAggregate (cost=50.94..51.01 rows=4 width=12)
Group Key: parent_id
-> Sort (cost=50.94..50.95 rows=4 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..50.90 rows=4 width=4)
Filter: (parent_id = ANY ('{1704,1707,1706,1705}'::integer[]))