MDX写法

求一个MDX写法
写一个mdx求当前地区的上级地区的环比,也就是
WITH MEMBER SS AS ([Measures].[Amount],([DiQU].[City].CurrentMember.Parent,[Date].[Month].CurrentMember.PrevMember))
SELECT {SS, [Measures].[Amount]} ON 0,
NONEMPTY([DiQU].[City].ALLMEMBERS * [Date].[Month].[Month].ALLMEMBERS)
ON 1 FROM DW


怎么SS老是NULL呢？


------解决方案--------------------
with member [Measures].[增长率] as '...'