方法一：普通联结
select cust_name, order_num from Customers C,Orders O where C.cust_id = O.cust_id order by cust_name,order_num;
方法二：使用内连接
select cust_name,order_num from Customers C inner join Orders O on C.cust_id = O.cust_id order by cust_name,order_num;
