LeetCode 196. Delete Duplicate Emails 删除重复的电子邮件（数据库）

题目：

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	[email protected]
2	[email protected]
3	[email protected]

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	[email protected]
2	[email protected]

Note:
Your output is the whole Person table after executing your sql. Use delete statement.

解答:

delete p1 from Person p1,Person p2 where p1.Email=p2.Email and p1.Id>p2.Id

delete p1 from Person p1 inner join Person p2 where p1.Email=p2.Email and p1.Id>p2.Id;