Oracle分组统计小计放在最后一行的处理

      在做统计查询，需要一个小计百分数放在最后一行，但不是最大最小的。处理过程如下记录：

SELECT '工单' AS BILTYPENAME,
               CASE WHEN BUREAU_ID IS NULL THEN '小计'
               ELSE BUREAU_ID
               END AS BUREAU_ID,
               CASE WHEN BILLSERVER_ENNAME IS NULL AND BUREAU_ID IS NOT NULL 
                 THEN '小计'
                 ELSE BILLSERVER_ENNAME
               END AS BILLSERVER_ENNAME,
               SUM(TOTAL) AS TOTAL,
               SUM(SUCC_NUM) AS SUCCNUM,
               SUM(FAIL_NUM) AS FAILNUM,
               DECODE(SUM(SUCC_NUM) / SUM(TOTAL),NULL,'0',1,'100',
                    TO_CHAR(ROUND(SUM(SUCC_NUM) / SUM(TOTAL), 4) * 100
                        ,'fm90.00')) || '%' 
               AS SUCCESSRATE,
               DECODE(BILLSERVER_ENNAME, NULL, -1, 1) 
                   *ROUND(SUM(SUCC_NUM) / SUM(TOTAL), 4) AS PAIXU
          FROM APP_ORIGINBILL_STAT_DAY ORIGINBILLOBJ
         WHERE 1 = 1
         GROUP BY ROLLUP(BUREAU_ID, BILLSERVER_ENNAME)
         ORDER BY BUREAU_ID NULLS LAST, PAIXU DESC

 这里百分数用 DECODE(SUM(SUCC_NUM) / SUM(TOTAL),NULL,'0',1,'100',
                    TO_CHAR(ROUND(SUM(SUCC_NUM) / SUM(TOTAL), 4) * 100 ,'fm90.00')) || '%'  来表示，这样最后排序时，有可能小计位于中间位置，通过 PAIXU 字段  DECODE(BILLSERVER_ENNAME, NULL, -1, 1)
                   *ROUND(SUM(SUCC_NUM) / SUM(TOTAL), 4)  重新进行降序排序，可以真正实现如图的排序。

 应该有更好的方法，希望能提供！