题解 | 返回顾客名称和相关订单号

# select C.cust_name,O.order_num
# from Customers C INNER join Orders O ON C.cust_id = O.cust_id
# order by C.cust_name ASC,O.order_num ASC;

select cust_name,
    (select order_num
    from Orders O
    where O.cust_id = Customers.cust_id) as order_num
from Customers
order by 
    cust_name ASC,
    order_num ASC;