QUERY PLAN
Limit (cost=59.11..59.11 rows=1 width=194)
-> Sort (cost=59.11..59.11 rows=1 width=194)
Sort Key: s.target_completed_at, s.updated_at DESC
-> Group (cost=59.09..59.10 rows=1 width=194)
Group Key: s.id, u.id
-> Sort (cost=59.09..59.09 rows=1 width=194)
Sort Key: s.id
-> Nested Loop (cost=0.14..59.08 rows=1 width=194)
-> Seq Scan on tbl_tasks s (cost=0.00..50.90 rows=1 width=190)
Filter: ((parent_id IS NULL) AND (head_of = 1001) AND (status = '0'::smallint))
-> Index Scan using tbl_users_pkey on tbl_users u (cost=0.14..8.16 rows=1 width=4)
Index Cond: (id = 1001)
Filter: (department_id = 4)