編寫一個 SQL 查詢,查找
Person
表中所有重複的電子郵箱。
示例:
+----+---------+
| Id | Email |
+----+---------+
| 1 | [email protected] |
| 2 | [email protected] |
| 3 | [email protected] |
+----+---------+
根據以上輸入,你的查詢應傳回以下結果:
+---------+
| Email |
+---------+
| [email protected] |
+---------+
說明:所有電子郵箱都是小寫字母。
這一題主要考察group by和having的用法了,代碼如下:
select Email from Person group by Email having count(Email)>1