Regarding rank based on comp of multiple fields

[d_koti24]

Hi All,

For Example:

i have 2 filters region and period.region values east,west and period values 1/08/2015,1/09/2015

suppose

east sales 10 for 01/08/2015

west sales 15 for 01/08/2015

so in 4th field rank i want to display 2, when i select region as east and period as 01/08/2015

                     i want to display 1, when i select region as west and period as 01/08/2015

selection: region : East ,period : 01/08/2015

region	cat	sales	rank
east	a	10	2

selection: region : west,period : 01/08/2015

region	cat	sales	rank
west	a	15	1

how to achieve this?

pfa