题解 | 返回prod_id为BR01的所有顾客的电子邮件
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 c.cust_email
from Customers c
where c.cust_id in (
select o.cust_id
from Orders o
left join OrderItems oi
on oi.order_num = o.order_num
where oi.prod_id = 'BR01'
)
