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, c.order_num, orderTotal
from Customers a, Orders b, 
(
    select order_num, sum(quantity*item_price)OrderTotal
    from OrderItems
    group by order_num
)c
where a.cust_id = b.cust_id and b.order_num = c.order_num
order by cust_name, c.order_num;