Calculate difference between invoice amount not based on date

[Evandam]

I'm looking for a way to calculate the difference between invoice amount, but not based on dates (month), but based on order of the invoice. So the difference between each invoice per client based on the fact that the invoice number increases each time.

the sample data looks like this:

[ryan_mayu]

could you pls provide the expected output?

[Evandam]

hi @ryan_mayu ,

it comes down to this:

[ryan_mayu · Accepted solution]

pls try this

Column = 
VAR _l=maxx(FILTER('Table (2)','Table (2)'[client]=EARLIER('Table (2)'[client])&&'Table (2)'[invoice]<EARLIER('Table (2)'[invoice])),'Table (2)'[invoice])
return if(ISBLANK(_l),BLANK(),'Table (2)'[amount]-maxx(FILTER('Table (2)','Table (2)'[client]=EARLIER('Table (2)'[client])&&'Table (2)'[invoice]=_l),'Table (2)'[amount]))

[Evandam]

@ryan_mayu 

Thank you! 
Almost works 100%. Only the last month of each years sums all the rows as you can see in the picture. Is there a way to fix this?

[ryan_mayu]

yes , because you have more than one value for that month, what's the expected otuput?

[Evandam]

aaah sorry... its because i use the month and year in the X-axis so the values get summed in the vissual. thanks 🙂

[ryan_mayu]

you are welcome