oracle自定义查询

SELECT
                  di.ID              ,
                  di.NAME            ,
                  di.USER_NAME       ,
                  di.IS_MAIN_DEMAND  ,
                  di.DEMAND_STATE    ,
                  di.CREATE_DATE     ,
                 case when di.DEMAND_STATE='CREATED' then 1
                  when di.DEMAND_STATE='SURVEING' then 2
                  when di.DEMAND_STATE='DISTRIBUTING' then 3
                  when di.DEMAND_STATE='DISTRIBUTED' then 4
                  when di.DEMAND_STATE='CLOSED' then 5 end RANK   
             FROM  Ali_DEMAND_INFO di
             ORDER BY RANK,di.CREATE_DATE DESC