how to create multiple filters when we are using tail as one of the filter?

if i use 开发者_如何转开发this one,my query is working...

" where ([PRODUCT].[All Product].[Debt Securities].[Available for Sale], [REPORT DATE.RUNNING_DATE].[All Report Date], [Transaction type].[All Transaction type].[PURCHASE INSTRUMENT])"

but i want to replace [REPORT DATE.RUNNING_DATE].[All Report Date] with Tail(Descendants([REPORT DATE].[All Report Date]))

i am getting error,when i am using this ..

"where ([PRODUCT].[All Product].[Debt Securities].[Available for Sale], Tail(Descendants([REPORT DATE].[All Report Date])) , [Transaction type].[All Transaction type].[PURCHASE INSTRUMENT])"

any help on this issue.....?

Thanking u in advace..

I don't quote understand your question, but I think you might want to look at using AGGREGATE, since the WHERE part of the query needs a tuple, not a set.