#用子查询,不知道会不会比连表慢,耗时35ms select courier_id, courier_name, ( base_salary + ( select sum(delivery_fee) from deliveries_info as d where delivery_date between '2024-07-01' and '2024-07-31' and d.courier_id=c.courier_id ) - ( select sum(expense_amount) from expenses_info as e where expense_date between '2024-07-01' and '2024-07-31' and e.courier_id=c.courier_id ) ) as total_income from couriers_info as c order by total_income desc;