Please Replace blank spaces with null values.

Hello Anonymous ,

you want to show the word "null" when it's blank ? 

if so then you reference your measure that is showing blank here where it says YourMeasure

Measure = IF(ISBLANK(YourMeasure, "Null", YourMeasure)

Anonymous 

The blanks in your table lack corresponding records, making them inaccessible for evaluation through a measure or any other method. I anticipate that the Power BI team will consider adding a feature to fulfill this requirement. I plan to create an idea request to address this need.

While I understand this doesn't address your issue, I hope it provides the answer you were looking for.