SQL取每行的最大记录

Select *
From   (Select *
        From   CUX_SEQ_TEST cst
        Where  1 = 1
               And cst.status = 'approved'
               And Not Exists (Select 1
                From   CUX_SEQ_TEST
                Where  time_number = cst.time_number
                       And app_num > cst.app_num)
        Order  By cst.app_id Asc --从小到大排序
        )
Where  rownum = 1 --取第一个审批人