LeetCode: 182. Duplicate Emails
LeetCode: 182. Duplicate Emails
Write a SQL query to find all duplicate emails in a table named Person.
+----+---------+
| Id | Email | +----+---------+
| 1 | a@b.com |
| 2 | c@d.com |
| 3 | a@b.com | +----+---------+For example, your query should return the following for the above table:
+---------+
| Email | +---------+
| a@b.com | +---------+Note: All emails are in lowercase.
解题思路
根据 Email 进行分组， 数据条数大于 1 的组的 Email 有重复的。
- GROUP BY: 对表进行分组
- HAVING: 为聚合结果指定条件
AC 代码
SELECT DISTINCT Email FROM Person GROUP BY Email HAVING COUNT(*) > 1
没有赛事奖项么？另外，项目经历字有点多哈，建议突出一下重点：用的什么技术，解决什么问题，达到什么效果。