Duplicate Emails Leetcode SQL

Write a SQL query to find all duplicate emails in a table named Person.


+----+---------+
| Id | Email   |
+----+---------+
| 1  | a@b.com |
| 2  | c@d.com |
| 3  | a@b.com |
+----+---------+
For example, your query should return the following for the above table:


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

Note: All emails are in lowercase.

这题用self join可以解决

# Write your MySQL query statement below
SELECT DISTINCT a.Email 
FROM Person a JOIN Person b
ON(a.Email=b.Email and a.Id<>b.Id)