题解 | #返回顾客名称和相关订单号以及每个订单的总价#

select cust_name, Orders.order_num,sum(quantity * item_price) as OrderTotal
from Customers
inner join Orders
on Customers.cust_id = Orders.cust_id 
inner join OrderItems
on Orders.order_num = OrderItems.order_num
group by Customers.cust_name,Orders.order_num
\\为什呢这里一定要group by,题目也没说要啊？？
order by Customers.cust_name,Orders.order_num