题解 | #返回购买 prod_id 为 BR01 的产品

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'));

牛客报错 unknown database test

莫名其妙，过段时间就通过了

可能是牛客服务器出错了？