QUERY PLAN
GroupAggregate (cost=48.92..48.94 rows=1 width=12)
Group Key: task_group_id
-> Sort (cost=48.92..48.92 rows=1 width=4)
Sort Key: task_group_id
-> Seq Scan on tbl_tasks (cost=0.00..48.91 rows=1 width=4)
Filter: ((parent_id IS NULL) AND (task_group_id = ANY ('{106,86}'::integer[])) AND (status = 0))