Delete Duplicate Emails
Question
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] |
+----+------------------+
Tags
- SQL
- DELETE function
Thought
Reference: https://discuss.leetcode.com/topic/10964/simple-solution
Code
-- Write your MySQL query statement below
DELETE p1
FROM Person p1, Person p2
WHERE p1.Email = p2.Email AND
p1.Id > p2.Id;