196. 刪除重複的電子郵箱

編寫一個 SQL 查詢，來刪除 Person 表中所有重複的電子郵箱，重複的郵箱裏只保留 Id 最小 的那個。

+----+------------------+
| Id | Email            |
+----+------------------+
| 1  | [email protected] |
| 2  | [email protected]  |
| 3  | [email protected] |
+----+------------------+
Id 是這個表的主鍵。

例如，在運行你的查詢語句之後，上面的 Person 表應返回以下幾行:

+----+------------------+
| Id | Email            |
+----+------------------+
| 1  | [email protected] |
| 2  | [email protected]  |
+----+------------------+

DELETE FROM Person WHERE Id NOT IN
(SELECT min_id FROM (SELECT MIN(Id) AS min_id From Person GROUP BY Email) AS MinId);

DELETE p2 FROM Person p1 JOIN Person p2 
ON p2.Email = p1.Email WHERE p2.Id > p1.Id;

DELETE p2 FROM Person p1, Person p2
WHERE p1.Email = p2.Email AND p2.Id > p1.Id;