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by Sumit Chourasia | Oct 16, 2020 | Category :coding | Tags : algorithm data-structure easy leetcode mysql sql

Delete Duplicate Emails - SQL - Easy - LeetCode

Delete Duplicate Emails - SQL - Easy - LeetCode

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  | 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  |
+----+------------------+
Note:

Your output is the whole Person table after executing your sql. Use delete statement.

# Write your MySQL query statement below
Delete p1 from Person p1, Person p2 Where p1.Email = p2.Email And p1.Id>p2.Id;

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