MySQL删除重复记录

举个例子,有一个表person,主键为id,email属性中有重复的记录。现在要求把重复的记录删除。

做法一：

DELETE a.*
FROM
     person a
LEFT JOIN (
     SELECT
          min(id) id,
          email
     FROM
          person
     GROUP BY
          email
     ORDER BY
          id
) b ON a.id = b.id
WHERE
     b.id IS NULL;