使用group后的order排序问题

[aifanwen]

为啥使用group后order排序没效果啊

SELECT class.class as classname1 ,file.classid,file.id,file.newname FROM class INNER JOIN file ON class.id = file.classid where file.id in(select max(file.id) from file group by file.classid order by file.classid desc)

[二月十六]

把order by 放到最外边，试试这个：

SELECT  class.class AS classname1 ,
        file.classid ,
        file.id ,
        file.newname
FROM    class
        INNER JOIN file ON class.id = file.classid
WHERE   file.id IN ( SELECT   MAX(file.id)
                       FROM     file
                       GROUP BY file.classid )
ORDER BY file.classid DESC

[aifanwen]

引用 1 楼 sinat_28984567 的回复:

把order by 放到最外边，试试这个：

SELECT  class.class AS classname1 ,
        file.classid ,
        file.id ,
        file.newname
FROM    class
        INNER JOIN file ON class.id = file.classid
WHERE   file.id IN ( SELECT   MAX(file.id)
                       FROM     file
                       GROUP BY file.classid )
ORDER BY file.classid DESC

多谢，好使！！