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,O.order_num,
#     (quantity * item_price) as OrderTotal
# from Customers C left join Orders O on C.cust_id = O.cust_id 
#     left join OrderItems OI on OI.order_num = O.order_num
# order by
#     C.cust_name ASC,
#     O.order_num ASC;

SELECT C.cust_name,O.order_num,(quantity * item_price) as OrderTotal
from Customers C,
    Orders O,
    OrderItems OI
where C.cust_id = O.cust_id and O.order_num = OI.order_num
order by
    C.cust_name ASC,
    O.order_num ASC;