mysql 数据去重

SET @r:=0;
UPDATE table SET id=(@r:=@r+1);

DELETE FROM `table`
WHERE
`去重字段名` IN (
    SELECT x FROM
    (
        SELECT `去重字段名` AS x 
        FROM `table` 
        GROUP BY `去重字段名` 
        HAVING COUNT(`去重字段名`) > 1
    ) tmp0
)
AND 
`递增主键名` NOT IN (
    SELECT y FROM
    (
        SELECT min(`递增主键名`) AS y 
        FROM `table` 
        GROUP BY `去重字段名` 
        HAVING COUNT(`去重字段名`) > 1
    ) tmp1
)