Here is my value :
VALUE -0,00398911382022891
and member which count this value
MEMBER [Date].[Percentage] AS
([Date].[AverageSaleNumberThisYear] - [Date].[AverageSaleNumberPreviouseYear] )/ [Date].[AverageSaleNumberThisYear].
If I use FORMAT_STRING = "Percent" I am getting this value : -0,40%, but i want exactly the same but without the %
sign.
You can use custom format strings in MDX. It sounds like you want
FORMAT_STRING = "0.00"
or
FORMAT_STRING = "Fixed"
I'm assuming that you didn't really want to multiple the value by 100, which is what "Percent" does)
If you do want it multiplied by 100, then do that in the expression:
MEMBER [Date].[Percentage] AS
100 * ([Date].[AverageSaleNumberThisYear] - [Date].[AverageSaleNumberPreviouseYear] ) / [Date].[AverageSaleNumberThisYear].