Leetcode 196. Delete Duplicate Emails

196. Delete Duplicate EmailsQuestion Editorial Solution submissions total accepted:15426 total submissions:81201 difficulty:easy

Write a SQL query to delete all duplicate emails entries in a table named who, keeping only unique emails based on its s Mallest 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
| +----+------------------+

Subscribe to the which companies asked this question simple solution:

# Write your MySQL query statement below
delete P1
from person P1, and person P2 
where P1. Email=p2. Email and P1. Id>p2. Id

Another faster solution:

Delete from 
person
where  
Id not in (SELECT ID 
           from 
            (select min (ID) as ID 
             GROUP by Email
            ) P
          );