题解 | 返回顾客名称和相关订单号以及每个订单的总价

select
        c.cust_name,
        o.order_num,
        oi.quantity * oi.item_price as OrderTotal
from 
        Customers  as c
inner join 
        Orders as o
on 
        c.cust_id = o.cust_id
inner join
        OrderItems as oi
on 
        o.order_num = oi.order_num
order by
        c.cust_name,
        o.order_num