关于order by 两个字段排序的问题？

[firstname]

如题：
我有两个字段需要排序。

SELECT * FROM job order by istj,fbtime desc
数据原为：

fbtime istj
2009-9-11 11:20 1
2009-9-11 11:23 0
2009-9-13 11:20 0
2009-9-12 11:20 1

我想得到的结果这个，但是用上面的语句不行，我哪儿错了，请问？

fbtime istj
2009-9-12 11:20 1
2009-9-11 11:20 1
2009-9-13 11:20 0
2009-9-11 11:23 0

[ACMAIN_CHM]

SELECT * FROM job  order by istj desc,fbtime desc

[wwwwb]

SELECT * FROM job order by istj desc,fbtime desc