题解 | ##
返回购买 prod_id 为 BR01 的产品的所有顾客的电子邮件(二)
https://www.nowcoder.com/practice/c7aa73afc41f4dfc925baebdd175c345
select a.cust_email as cust_email from Customers as a where a.cust_id in ( select b.cust_id as cust_id from Orders as b inner join OrderItems as c on b.order_num = c.order_num where c.prod_id = 'BR01' );