- (Except) (MDX)
Performs a set operation that returns the difference between two sets, removing duplicate members.
Syntax
Set_Expression - Set_Expression
Parameters
- Set_Expression
A valid Multidimensional Expressions (MDX) expression that returns a set. 
Return Value
A set that contains members that are not shared by both specified parameters.
Examples
The following example demonstrates the use of this operator:
// This query shows the quantity of orders for all product categories
// with the exception of Components.
SELECT 
   [Measures].[Order Quantity] ON COLUMNS,
   [Product].[Product Categories].[All].Children 
   - [Product].[Product Categories].[Components] ON ROWS
FROM
    [Adventure Works]