[182\. 查找重復的電子郵箱](https://leetcode-cn.com/problems/duplicate-emails/)
===
### 今天面試遇到這個問題,恨啊!沒有作這一到題 哭
### 解題 方法一
`SELECT Email from Person GROUP BY Email having count(Email)>1`
### 解題 方法二
```
SELECT Email from
(
SELECT Email,count(Email) AS num
FROM Person
GROUP BY Email
) as ns
where num > 1;
```
