不想写第二遍的刷题笔记

世界级打野都是rush大龙的

Duplicate Emails

LeetCode 182

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.

Solution

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