Openingbalancemonth vs own calculation difference

[KevinParijs]

Hello,

I'm trying to report on the Opening/Closing Balance by month, but for some reason, my very first Opening Balance (using the OpeningBalanceMonth function is not showing any data).
When I rewrite the measure it does show a number.
Can someone tell me why this is happening? 

Measure 1 (using the OpeningBalanceMonth function)

Measure 2 (using own logic)

Below you see the difference between the two measures.
I would expect that the measure 1 (with the use of OpeningBalanceMonth function) would return the exact same thing as measure 2 (with the use of own logic)

Regards,

Kevin

[v-jianboli-msft · Accepted solution]

Hi @KevinParijs ,

Approve with @KevinParijs , the Microsoft Docs is  not very clearly, although it returns a scalar value that represents the expression evaluated at the first date of the month in the current context, the real calculate logic of this function is evaluating the specified expression for the date corresponding to the end of the previous month after applying all the filters.

Here is a simple sample:

From the picture, you can see that the opening balance of January 2022 is blank, that is because there is no data of December 2019, the opening balance of January 2022 would be the closing balance of December 2019. And if you continue to view the data of February 2022, you can see the opening balance will be the closing balance of January 2022.

That is why your first measure does not work.

For more details, please refer to:

OPENINGBALANCEMONTH Function DAX.

OPENINGBALANCEMONTH, OPENINGBALANCEQUARTER, OPENINGBALANCEYEAR – DAX Guide - SQLBI 

Best Regards,

Jianbo Li

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[amitchandak]

@KevinParijs , Opening balance return data on the last date of the previous month. So it will not work the same as what you have

Refer https://www.youtube.com/watch?v=6lzYOXI5wfo&t=37s

[KevinParijs]

Thank you for your response, but the Microsoft Docs is showing the following definition:

"Evaluates the expression at the first date of the month in the current context"

https://docs.microsoft.com/en-us/dax/openingbalancemonth-function-dax

This made me think that by using this function it would evaluate the 1/january/2021.