题解 | #返回顾客名称和相关订单号以及每个订单的总价#

先联结Customers、Orders这两个表，再联结OrderItems表；

select cust_name,
        order_num ,
        round((select sum(quantity *item_price ) 
               from OrderItems 
               where OrderItems.order_num =Orders.order_num),3) OrderTotal
from Customers ,Orders 
where Customers.cust_id = Orders.cust_id 
order by cust_name,order_num;