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] |
+

寫出 SQL Query 從 Person 找出所有有重複的 email 資料。

範例

For example, your query should return the following for the above table:

+---------+
| Email   |
+---------+
| [email protected] |
+---------+

根據上面的例子，應該要回傳這樣的表。

解題

首先用 GROUP BY 將 Email 分組起來。

再來利用 HAVING 找出分組後誰的 Email 數量大於 1 的即可。

SELECT Email
FROM Person
GROUP BY Email
HAVING count(Email) > 1