KEY
The value of the member key in the original data type. KEY has the same value as KEY0 for non-composite keys and KEY property is null for composite keys.
Syntax
Member_Expression.KEY
Input Parameters
N/A
Return Value
Returns the member key value. The type depends on the mapped column binding.
Example
Sales for "Red" members only, else 0.
IIF([Color Dimension].[Color].CurrentMember.KEY = "Red",[Measures].[salesamount1], 0)