BEx Query requirement

Hi

I have a defined query with Material in row and with three keyfigures price (current year), price (current year -1) and price (current year - 3) in column.

Current year is input variable of query i.e. 2011. It works fine.

Now my requirement is to define a new cal. key figure which should show the least (minimum) of all above three keyfigures. Moreover I have identify the year

of least (minimum) price to calculate another cal. key figure/restriced key figure.

Thanks