mysql删除重复记录的例子

SELECT *  FROM ip_one WHERE id NOT IN ( SELECT * FROM (SELECT MIN(id)  FROM ip_one GROUP BY user_id )a )
DELETE FROM ip_one WHERE id NOT IN ( SELECT * FROM (SELECT MIN(id)  FROM ip_one GROUP BY user_id )a )

 

mysql 5.1.4中SELECT * FROM (SELECT MIN(id)  FROM ip_one GROUP BY user_id )a 别名是必须的，否则会报错。