[LeetCode] 196. Delete Duplicate Emails_Easy tag: SQL

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]  |
+----+------------------+

Note:

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

Code

DELETE p2 FROM Person AS p1, Person As p2 WHERE p1.Email = p2.Email AND p1.Id < p2.Id

原文地址：https://www.cnblogs.com/Johnsonxiong/p/9490988.html

时间： 2024-10-29 16:25:00

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