从mysql数据库删除重复记录只保留其中一条

DELETE FROM saler_login
WHERE username IN(
	SELECT t.username FROM
	(SELECT id,username FROM saler_login
		GROUP BY username
		HAVING COUNT(1)>1
	) t
	) AND id NOT IN 
	(SELECT dt.minid FROM 
		(SELECT MIN(id) AS minid FROM saler_login
			GROUP BY username
			HAVING COUNT(1)>1
		) dt
	);