/**
Problem Name : Delete Duplicate Emails
Problem URL : https://leetcode.com/problems/delete-duplicate-emails/
Description :
Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id.
Difficulty : Easy
Language : MySQL
Category : Database
*/
DELETE p2 FROM Person p, Person p2
WHERE p.id < p2.id
AND p.email = p2.email;