mysql删除重复的数据，只保留一条

DELETE 
FROM
	user
WHERE
	u_id IN(
	select u_id from (
SELECT
	u_id 
FROM
	user
WHERE
	id IN ( SELECT id FROM user GROUP BY id HAVING count( id ) > 1 ) 
	AND u_id not IN ( SELECT min( u_id  ) FROM user GROUP BY id HAVING count( id  ) > 1 ) ) temp
	)