Listing A: Code That Uses 2 Calculated Members to Solve July Puzzle
WITH
  MEMBER [Measures].[LastSales] AS 'IIF( [Time].CURRENTMEMBER.LEVEL.ORDINAL = 2,
     ([Time].CURRENTMEMBER, [Store Sales]), [NonEmptySales] )'
  MEMBER [Measures].[NonEmptySales] AS 
'((Filter(DESCENDANTS([Time].CURRENTMEMBER,[Month]), NOT ISEMPTY([Store 
Sales]))).ITEM( COUNT(Filter(DESCENDANTS([Time].CURRENTMEMBER,[Month]), NOT 
ISEMPTY([Store Sales]) ) )-1).ITEM(0), [Store Sales])'
SELECT { [1997].CHILDREN } ON COLUMNS,
  DESCENDANTS([Customers].[All Customers].[USA].[CA].[Los Angeles], [Customers].[Name]) 
ON ROWS
FROM Sales
WHERE ([LastSales])