LeetCode-MySQL-182. 查找重复的电子邮箱

SQL架构

编写一个 SQL 查询，查找 Person 表中所有重复的电子邮箱。

示例：

+----+---------+
| Id | Email   |
+----+---------+
| 1  | a@b.com |
| 2  | c@d.com |
| 3  | a@b.com |
+----+---------+

根据以上输入，你的查询应返回以下结果：

+---------+
| Email   |
+---------+
| a@b.com |
+---------+

说明：所有电子邮箱都是小写字母。

# Write your MySQL query statement below
select distinct P1.Email
from Person as P1, Person as P2
where P1.Id != P2.Id and P1.Email = P2.Email

# Write your MySQL query statement below
select Email
from Person 
group by Email
having count(Id) > 1