MySql里删除重复数据,但保留一条

DELETE 
FROM
	news 
WHERE
	id IN (
	SELECT
		id 
	FROM
		(
		SELECT
			id 
		FROM
			news 
		WHERE
			md5 IN ( SELECT md5 FROM news GROUP BY Md5 HAVING COUNT( Md5 ) > 1 ) 
			AND id NOT IN ( SELECT MIN( id ) FROM news GROUP BY Md5 HAVING COUNT( Md5 ) > 1 ) 
		) AS tmp 
	)