Previous month returning value

[junkforhr]

Hello All,

I have the below code and it works fine apart from the fact that the most recent month and first month in the range are not giving me the result I want.

In the example below my data does not have data for September 2022, so I am not sure why this is showing in the table.

Below is split into two tables, 1st table are what I get now and the 2nd table is my desired results.

Hoping someone can assist, as it's only my 5th day using power bi.

Current Results

Year	Month	COUNT_ACT	Last Month Difference
2022	September		10,000
2022	August	10,000	- 1,000
2022	July	11,000	- 1,000
2022	June	12,000	4,000
2022	May	8,000	8,000

Desired Results

Year	Month	COUNT_ACT	Last Month Difference
2022	September
2022	August	10,000	- 1,000
2022	July	11,000	- 1,000
2022	June	12,000	4,000
2022	May	8,000

Last Month Difference = sum( Dataset[COUNT_ACT])-CALCULATE(sum( Dataset[COUNT_ACT]),PREVIOUSMONTH( Dataset[ReportingMonth].[Date]))

 

[Leo Skywalker]

It's giving you the result you requested: the difference of one month and the previous.
When a blank cell is found, then zero is asumed, so you're getting: 10000-blank = 10000-0=10000

You need to change your code, so that when a blank cell is found, to return blank as well.
also, you would need to adjust that the following month the calculation to be performed with the last found value.

 

[junkforhr]

It's giving you the result you requested: the difference of one month and the previous.
When a blank cell is found, then zero is asumed, so you're getting: 10000-blank = 10000-0=10000

You need to change your code, so that when a blank cell is found, to return blank as well.
also, you would need to adjust that the following month the calculation to be performed with the last found value.

I guess that's what I'm asking, how do I do that