题解 | SQL34#返回购买 prod_id 为 BR01 的产品的所有顾客的电子邮件（一）#

分析

1. 从OrderItems表返回order_num。select order_num from OrderItems where prod_id='BR01'
2. 从Orders表返回cust_id。select cust_id from Orders where order_num in（）
3. 从Customers表返回cust_email

代码

select cust_email from Customers
where cust_id in
(select cust_id from Orders
where order_num in
    (select order_num from OrderItems 
    where prod_id='BR01'
     )
 )