subtraction month by month by segmentation

[TTac]

Hello everyone,

 I'm new to all of this. Trying to subtract value month by month by segment.  Could anyone help me with a measure formula in apps?

Expected result example of measure Diff:

Period	Segment	Value	Diff
2021-01-31	A	10
2021-01-31	B	12
2021-01-31	C	8
2021-01-31	D	9
2021-02-28	A	15	5
2021-02-28	B	14	2
2021-02-28	C	7	-1
2021-02-28	D	13	4
2021-03-31	A	20	5
2021-03-31	B	19	5
2021-03-31	C	6	-1
2021-03-31	D	5	-8

[Almen · Accepted solution]

I think if you turn your table into a pivot table you can use Value-before(Value) to get your desired result.

So dimension would be Segment for rows and Period for columns. Your measure Value-before(Value)