Expression Question

[dataexplorer]

Hello QlikView Community,

I am trying to write an expression in a Text Object, where it does the following

(Avg Price (current period)-Avg Price(baseline period))*Qty(current period)

Then sum the above expression to calculate inflation/deflation

The expression needs to be on the front end, so that the user can select the current period and baseline period. Thank you in advance for assistance. 

Here is a sample data 

Current period - Nov-2022 Baseline Period - Dec-2021

Month-Year	Material-ID	Inv. Value	Stock Qty	Avg Price
Nov-22	AAA	942.39	37	25.47
Nov-22	BBB	942.34	2	471.17
Nov-22	CCC	941.5	14	67.25
Nov-22	DDD	941.5	14	67.25
Nov-22	EEE	940.96	8	117.62
Nov-22	XXX	940.3	5	188.06
Dec-21	AAA	85.29	3	28.43
Dec-21	BBB	475.15	1	475.15
Dec-21	CCC	941.5	14	67.25
Dec-21	DDD	295.35	11	26.85
Dec-21	EEE	940.96	8	117.62
Dec-21	XXX	1013.1	5	202.62

[dataexplorer]

Hello, any ideas? I am still stuck