Difference between columns coming from same row in matrix

[Anonymous]

I have a sample data:

Week number	Category	Sales
1	MessT	1234
2	WerkZ	2345

From this I created a matrix table which calculates a sum of sales in a given week. it looks like in a screenshot.

I read docs about how to create a measure with differences between these categories and a % diff, but I am getting blanks. Why is that? 

From two tutorials I am trying two columns:

the diff2 column is 

Diff2 = CALCULATE(
    SUM([items.netRevenue]),FILTER(invoices_granular, invoices_granular[WeekNum]=MAX(invoices_granular[WeekNum]) 
    - CALCULATE(
    SUM(invoices_granular[items.netRevenue]),FILTER(invoices_granular,invoices_granular[WeekNum]=MIN(invoices_granular[WeekNum]) 
))
))

and Difference between Cat is:

Difference btw Cat = 
    IF (
        HASONEVALUE(invoices_granular[WeekNum]),
        BLANK(),
        CALCULATE( 
            SUM(invoices_granular[items.netRevenue]),
            FILTER(invoices_granular, invoices_granular[WeekNum] = MAX(invoices_granular[WeekNum]))
        )
        - CALCULATE(
            SUM(invoices_granular[items.netRevenue]),
            FILTER(invoices_granular,invoices_granular[WeekNum] = MIN(invoices_granular[WeekNum]))
        )
    )

[amitchandak]

@Anonymous , Make sure you have separate week or date table and then try approch like

Have these new columns in Date Table, Week Rank is Important in Date/Week Table

Week Rank = RANKX('Date','Date'[Week Start date],,ASC,Dense)
OR
Week Rank = RANKX('Date','Date'[Year Week],,ASC,Dense) //YYYYWW format

These measures can help
This Week = CALCULATE(sum('Table'[Qty]), FILTER(ALL('Date'),'Date'[Week Rank]=max('Date'[Week Rank])))
Last Week = CALCULATE(sum('Table'[Qty]), FILTER(ALL('Date'),'Date'[Week Rank]=max('Date'[Week Rank])-1))

Power BI — Week on Week and WTD
https://medium.com/@amitchandak.1978/power-bi-wtd-questions-time-intelligence-4-5-98c30fab69d3
https://community.powerbi.com/t5/Community-Blog/Week-Is-Not-So-Weak-WTD-Last-WTD-and-This-Week-vs-Last-Week/ba-p/1051123
https://www.youtube.com/watch?v=pnAesWxYgJ8

[Anonymous]

Hi @amitchandak This is not exactly what I need I think.

I made a separate date table, and changed the formula and still I get blank values. 

I want to calculate a difference  for categories 0 as in screenshot, sales on 7/7/23 for category Messtechnik are 11k, and for category Werkzeuge are 4,9k. I want the difference to populate and show 6k. Instead I am getting blanks.

I followed tutorials and not sure what I missed