Come from : [https://leetcode-cn.com/problems/delete-duplicate-emails/]
196. Delete Duplicate Emails
1.Question
Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id.
+----+------------------+
| Id | Email |
+----+------------------+
| 1 | john@example.com |
| 2 | bob@example.com |
| 3 | john@example.com |
+----+------------------+
Id is the primary key column for this table.
For example, after running your query, the above Person table should have the following rows:
+----+------------------+
| Id | Email |
+----+------------------+
| 1 | john@example.com |
| 2 | bob@example.com |
+----+------------------+
Note:
Your output is the whole Person table after executing your sql. Use delete statement.
2.Answer
easy 类型题目。简单的SQL语句查询（今天是水一下，哈哈，端午节快乐）.
AC代码如下：
# Write your MySQL query statement below
delete p1 from Person p1, Person p2
where p1.Email=p2.Email and p1.Id>p2.Id
3.我的收获
fighting。。。
2019/6/6 胡云层 于南京 95