/*查询重复数据*/
SELECT
	* 
FROM
	index_price 
WHERE
	( fund_number, date ) IN ( SELECT fund_number, date FROM index_price GROUP BY fund_number, date HAVING count(*)> 1 ) 
ORDER BY
	fund_number,
	date DESC;
	
	/*删除重复数据，一次只删除每组重复数据中的一条数据，若一组数据多次重复，要执行多次*/
	
DELETE 
FROM
	index_price 
WHERE
	id IN (
	SELECT
		id 
	FROM
		(
		SELECT
			max( id ) id 
		FROM
			index_price 
		WHERE
			( fund_number, date ) IN ( SELECT fund_number, date FROM index_price GROUP BY fund_number, date HAVING count(*)> 1 ) 
		GROUP BY
			fund_number,
			date 
		) t 
	)