[LeetCode] 196. Delete Duplicate Emails_Easy tag: SQL
Posted
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了[LeetCode] 196. Delete Duplicate Emails_Easy tag: SQL相关的知识，希望对你有一定的参考价值。
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
以上是关于[LeetCode] 196. Delete Duplicate Emails_Easy tag: SQL的主要内容，如果未能解决你的问题，请参考以下文章
[LeetCode] 196. Delete Duplicate Emails_Easy tag: SQL