182. Duplicate Emails

Giới thiệu bài toán

Table: Person

Column Name	Type
id	int
email	varchar

id is the primary key (column with unique values) for this table.
Each row of this table contains an email. The emails will not contain uppercase letters.

Yêu cầu

Write a solution to report all the duplicate emails. Note that it's guaranteed that the email field is not NULL.

Return the result table in any order. The result format is in the following example.

Example 1:

Email
`a@b.com`

SELECT email 
FROM Person 
GROUP BY email 
HAVING COUNT(id) > 1;