Question

我刚开始学习MySQL，对表别名感到很困惑。当我尝试运行此查询时，它告诉我查询无效：

select customer_number 
from 
(select customer_number, count(*) as num
from orders
group by customer_number) as tmp
where num = (select max(num) in tmp)

我知道有一种简单的方法可以做到这一点，我只是为什么我的代码无法工作而感到困惑，非常感谢！

Answer 1

您可以使用LIMIT修改此查询：

SELECT customer_number
FROM orders
GROUP BY customer_number
ORDER BY COUNT(*) DESC
LIMIT 1

在子查询中使用表别名与where子句对齐

1 个答案: