QUERY PLAN
Limit (cost=62.53..62.55 rows=10 width=195)
-> Sort (cost=62.53..62.71 rows=75 width=195)
Sort Key: s.created_at
-> HashAggregate (cost=60.16..60.91 rows=75 width=195)
Group Key: s.id, u.id
-> Nested Loop (cost=0.00..59.78 rows=75 width=195)
-> Seq Scan on tbl_users u (cost=0.00..8.16 rows=1 width=4)
Filter: ((id = 5064) AND (department_id = 10))
-> Seq Scan on tbl_tasks s (cost=0.00..50.87 rows=75 width=191)
Filter: ((parent_id IS NULL) AND (head_of = 5064) AND (status = '1'::smallint))