I had some issues with my Power BI Desktop. My pain was that there is this column full with number except a few 'blank' records. At least, there is no value displayed, thus I assumed the field is bla...
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Community Support
Community SupportHi DouweMeer,
The Null column value in Excel is a empty string. In DAX, not all functions treat the nulls and empty string as the same.
For ISBLANK() function, it returns true when the referenced column value is null. In your scenairo, as the Null column values is not a null actually, it returns 0. You can use BLANK() function to get true result as this function treat the nulls and empty string as the same.
Reference:
https://docs.microsoft.com/en-us/dax/blank-function-dax
https://docs.microsoft.com/en-us/dax/isblank-function-dax
Best Regards,
Qiuyun Yu