【MySQL】【leetcode】 Delete Duplicate Emails解题报告

来源:转载

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.

1 [email protected] 2 [email protected] 3 [email protected]
Id Email

Id is the primary key column for this table.
For example, after running your query, the above Person table should have the following rows:

1 [email protected] 2 [email protected]
Id Email

题目来源:https://leetcode.com/problems/delete-duplicate-emails/

代码

Email重复的话,保留ID最小的那条记录,其余的删除。

#方法一:# Write your MySQL query statement belowdelete from Personwhere Id not in ( select * from ( select MIN(Id) from Person group by Email ) as tb);#方法二:# Write your MySQL query statement belowdelete p1 from Person as p1, Person as p2where p1.Email = p2.Email and p1.Id > p2.Id;


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