WITH 
	SET CustomerSelected AS
		NonEmpty(
			EXISTING([Customer].[ID].Children)
			,[Measures].[Data Count]
		)
	 MEMBER [Measures].[FBD] AS CDate(IIF([Customer].[ID].currentmember.Properties("FTB Date") ="", "01.01.1900", [Customer].[ID].currentmember.Properties("FTB Date")))
	 MEMBER [Measures].[LBD] AS CDate(IIF([Customer].[ID].currentmember.Properties("LTB Date") ="", "01.01.1900", [Customer].[ID].currentmember.Properties("LTB Date")))
	 MEMBER [Measures].[DD] AS DateDiff("D", [Measures].[FBD], [Measures].[LBD])
	 MEMBER [Measures].[A] AS SUM(EXISTS([Customer].[ID].currentmember), [Measures].[DD])
SELECT {[Measures].[FBD], [Measures].[LBD], [Measures].[DD], [Measures].[A]} ON COLUMNS,
	TOPCOUNT([Customer].[ID].Members, 100) ON ROWS
FROM [Cube]
WHERE [Date].[Dates].[Month-Year].&[March 2017]