Adhoc Reports - How to use set analysis in Expression

[#1]

Hi All ,

I have a scenario in which the following set Analysis has to be used in Adhoc Reporting

Sum({$<YEAR = {$(=Max(YEAR)-1)}>} VOLUME)

I have 2 Table : Dimension , Measures

Dimensions are

CHANNEL

REGION

COUNTRY

Measures are

YTDN-1

etc

How can i add the above set analysis in a way that it works in Expression for Adhoc Reporting?

Thanks