查询单表中多个字段同时重复的数据

SELECT
    *
FROM
	table 
WHERE
	id NOT IN (
	SELECT
		temp.mid 
	FROM
		( SELECT min( id ) AS mid FROM table em GROUP BY em.cid, em.mem_id ) AS temp 
	);

删除重复数据只保留一条

DELETE 
FROM
	gm_vip_member 
WHERE
	id NOT IN (
	SELECT
		temp.mid 
	FROM
		( SELECT min( id ) AS mid FROM gm_vip_member em GROUP BY em.cid, em.mem_id ) AS temp 
	);