LeetCode: 删除重复的邮箱地址

问题

Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id.

+----+------------------+
| Id | Email            |
+----+------------------+
| 1  | john@example.com |
| 2  | bob@example.com  |
| 3  | john@example.com |
+----+------------------+
Id is the primary key column for this table.

For example, after running your query, the above Person table should have the following rows:

+----+------------------+
| Id | Email            |
+----+------------------+
| 1  | john@example.com |
| 2  | bob@example.com  |
+----+------------------+

翻译

从Person表中删除所有重复的邮箱，仅保留 id 最小的邮箱。

解决方法

DELETE
FROM
    Person
WHERE
    id NOT IN (
        SELECT
            t.id
        FROM
            (
                SELECT
                    `Email`,
                    min(id) AS id
                FROM
                    Person
                GROUP BY
                    `Email`
            ) t
    )