Hi Mack ,

I'm on a roll...even simpler...using the "null" value brings back the first member of a set on the same level as the current member...only works if you use the range : (colon)

-- Previous 3 month sales using tail and "null"

WITH MEMBER [Measures].[PrevThreeMonthSales] AS 'SUM(Tail(null:[Order Date].[CalendarHierarchy].CurrentMember,3), [Measures].[Sales Amount])'

SELECT {[Measures].[Sales Amount], PrevThreeMonthSales} ON 0,

[Order Date].[CalendarHierarchy].[Month] On 1

FROM MyFirstCube

Cheers

Robin