LeetcodeDuplicate Emails
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题目链接：https://leetcode.com/problems/duplicate-emails/
题目：
Write a SQL query to find all duplicate emails in a table named Person.
+—-+———+
| Id | Email |
+—-+———+
| 1 | [email protected] |
| 2 | [email protected] |
| 3 | [email protected] |
+—-+———+
For example, your query should return the following for the above table:
+———+
| Email |
+———+
| [email protected] |
+———+
Note: All emails are in lowercase.
思路：
group by 将数据划分成一组一组的。。那么根据什么来划分呢，就是根据having后面的条件，一般是函数 如count sum
算法：
select Email from Person group by Email having count(Email)>1以上是关于LeetcodeDuplicate Emails的主要内容，如果未能解决你的问题，请参考以下文章
SELECT * FROM people、people_emails、members 或 INNER JOIN [重复]