MDX - TopCount plus 'Other' or 'The Rest' - mdx

Question

I have created an MDX query which calculates the TOP 10 ZipCodes (according to my Patient Stay measure) as such:
WITH
MEMBER [Discharge Date].[Y-M-D].[ Aggregation] AS 'AGGREGATE( EXISTING { [Current Month] } )', SOLVE_ORDER = 0
SELECT
NON EMPTY { [Measures].[Patient Stays] }
ON COLUMNS,
TOPCOUNT({ ORDER( HIERARCHIZE( { [Patient].[ByZipcode].[All].CHILDREN } ), ( [Measures].[Patient Stays] ), BDESC ) }, 10)
ON ROWS
FROM [Patient Stay]
WHERE ( [Discharge Date].[Y-M-D].[ Aggregation], [Facility].[ByAffiliation].CURRENTMEMBER, [Facility].[ByRegion].CURRENTMEMBER )
This query is used to populate a PerformancePoint 100% Stacked Bar chart. The client has asked that since this is a !00% based chart, we lump the rest of the zip codes into an "Other" field, such that there should be 11 values: one for each of the top 10, and an eleventh which is a sum of the remaining Zip Codes.
I am an extreme novice to MDX, but this doesn't souund like it should be impossible. Does anyone have any ideas or suggestions?

Answer 1

I'll do my best with untested code, so here goes:
WITH
MEMBER [Discharge Date].[Y-M-D].[ Aggregation] AS 'AGGREGATE( EXISTING { [Current Month] } )', SOLVE_ORDER = 0
SET [Top10ZipCodes] AS
(TOPCOUNT({ ORDER( HIERARCHIZE( { [Patient].[ByZipcode].[All].CHILDREN } ), ( [Measures].[Patient Stays] ), BDESC ) }, 10))
MEMBER [Patient].[ByZipCode].[OtherZipCodes] AS
(AGGREGATE({EXCEPT([Patient].[ByZipCode].Members, [Patient].[ByZipCode].[Top10ZipCodes])}))
SELECT
NON EMPTY { [Measures].[Patient Stays] }
ON COLUMNS,
{[Top10ZipCodes], [Patient].[ByZipCode].[OtherZipCodes]}
ON ROWS
FROM [Patient Stay]
WHERE ( [Discharge Date].[Y-M-D].[ Aggregation], [Facility].[ByAffiliation].CURRENTMEMBER, [Facility].[ByRegion].CURRENTMEMBER )
What this does is creates a set of your top 10 ZIP codes, and then aggregates (different than sum!!!) all the ZIP codes, with the exception of your top 10.
Also, if this is a common set (top 10 ZIP codes), you may want to make a set on the cube, where you can reuse it ad nauseum, without having to change every MDX query you have.
Cheers,
Eric