题解 | #返回顾客名称和相关订单号#

select cust_name,
(
    select order_num FROM Orders AS b 
    WHERE  b.cust_id = a.cust_id
) order_num
FROM Customers AS a
ORDER BY cust_name,order_num

select cust_name, order_num
FROM Customers AS ct
JOIN Orders AS od
ON ct.cust_id = od.cust_id
ORDER BY cust_name,order_num