[LeetCode]Duplicate Emails,解题报告，leetcodeemails

目录

• 目录
• 题目
• 解题思路
• AC SQL

---

题目

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

题目需要从Person表中找出重复出现的Email。

解题方法也很简单：按照Email分组，然后找出id出现次数超过1的Email，即使用group by 和 having 实现。

---

AC SQL

select Email from Person group by Email having count(id) > 1;