题解 | #返回顾客名称和相关订单号以及每个订单的总价#

select Customers.cust_name, Orders.order_num, (select sum(quantity*item_price) from OrderItems where OrderItems.order_num = Orders.order_num) as OrderTotal
from Customers, Orders, OrderItems
where Customers.cust_id = Orders.cust_id and Orders.order_num = OrderItems.order_num
order by 1, 2;