Last updated on January 21st, 2025 at 03:44 am

Here, we see a Delete Duplicate Emails LeetCode Solution. This Leetcode problem is solved using MySQL and Pandas.

List of all LeetCode Solution

Level of Question

Easy

Delete Duplicate Emails LeetCode Solution

1. Problem Statement

Column Name	Type
id	int
email	varchar

id is the primary key (column with unique values) for this table. Each row of this table contains an email. The emails will not contain uppercase letters.

Write a solution to delete all duplicate emails, keeping only one unique email with the smallest id.

For SQL users, please note that you are supposed to write a DELETE statement and not a SELECT one.

For Pandas users, please note that you are supposed to modify Person in place.

After running your script, the answer shown is the Person table. The driver will first compile and run your piece of code and then show the Person table. The final order of the Person table does not matter.

The result format is in the following example.

Example 1:
Input:

id	email
1	john@example.com
2	bob@example.com
3	john@example.com

Output:

id	email
1	john@example.com
2	bob@example.com

Explanation: john@example.com is repeated two times. We keep the row with the smallest Id = 1.

2. Code Implementation in Different Languages

2.1 Delete Duplicate Email MySQL

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