Filter mdx query result

Question

I have a MDX query that return result like this:

Customer | Store | Sales

A | Store_1 | 123.45

A | Store_2 | 234.56

B | Store_2 | 345.67

B | Store_3 | 456.78

C | Store_1 | 543.21

C | Store_3 | 654.32

How the query should look to have result that show only one row per customer with the first store only:

A | Store_1 | 123.45

B | Store_2 | 345.67

C | Store_1 | 543.21

Update: Actual query

SELECT

  [Measures].[Sales] ON COLUMNS,

  NON EMPTY(
  [Customers].[User].[User], [Stores].[Store].[Store]
  ) ON ROWS

FROM SALES

Answer 1

If I run this:

SELECT 
  [Measures].[Internet Sales Amount] ON 0
 ,
    [Product].[Category].[Category]
  * 
    [Customer].[Customer Geography].[Country] ON 1
FROM [Adventure Works];

I get the following:

If I just want the first for each category I need to do something like this:

WITH 
  SET [cats] AS 
    [Product].[Category].[Category] 
  SET [cats_country] AS 
    Generate
    (
      [cats] AS S
     ,
        S.Current
      * 
        Head(NonEmpty([Customer].[Customer Geography].[Country],S.Current))
    ) 
SELECT 
  [Measures].[Internet Sales Amount] ON 0
 ,[cats_country] ON 1
FROM [Adventure Works];

Results in this: