COMPARE Value differences between 2 columns by DATE

[Anonymous]

Hi the community, 

I'm making progress in DAX but i'm still stucked on begginer issues. 

Imagine i have this kind of data : 

Vendor	Part	Condition	Quantity	Net Order	Year
Jack aero	1123040	Scrap	5	1000	2018
Jack aero	1123040	Scrap	8	2000	2019
Jack aero	1132050	Overhaul	2	1500	2018
Jack aero	1132050	Overhaul	6	3000	2019

I would like to know how to calculate the difference in term of quantity and net order between 2018-2019 by part and by Vendor. 

By example a column or a formula which gave me like for the part 1123040 -3 and 1000$

Thank you so much in advance for any help !! 

Best

[Anonymous]

You can start by creating measures to calculate the amounts in the periods you want to compare. The years in this example could be fetched from selections in slicers, current year or something else in the below formulas.

QuantityCurrentYear =
VAR CurrentYear = 2019
RETURN
    CALCULATE (
        SUM ( Orders[Quantity] );
        KEEPFILTERS ( Orders[Year] = CurrentYear )
    )

QuantityPreviousYear =
VAR PrevYear = 2018
RETURN
    CALCULATE (
        SUM ( Orders[Quantity] );
        KEEPFILTERS ( Orders[Year] = PrevYear )
    )

Then create the measure that groups on vendor and part and calculates the difference:

QuantityDifference =
SUMX (
    SUMMARIZE ( Orders; 'Orders'[Vendor]; Orders[Part] );
    [QuantityCurrentYear] - [QuantityPreviousYear]
)

(if you use english settings, replace ; with ,)

Best Regards // Ulf

[Anonymous]

Honnestly this is great ! thank you for this first step. 

But the only problem is that i have is the following one : 

Vendor	Part	Order Quantity	Order Difference	Year
Jack aero	112000	5	-5	2018
Jack aero	112000	7	7	2019
BUSAIR aviation	150000	10	-10	2018
BUSAIR aviation	150000	20	20	2019
total		42	12	2019

But what i would like to see is where i have the bigger difference by part number. Or, in this case i just see for the total or if i'm selectionning one part with a slicer. 

On this point, i would like a coulum, like "2019 difference", where you could see for each part easily the difference before the previous year (2018). 

One row out 2 will show a data... something like that 

Part	2019 difference
112000	2
15000	10
total	12

thanks again for your help !