Data Factory Compare fuction

Hi,

I have one question regarding the Compare function in Data Factory. I have been working on a project, and I noticed that when I compare null values in an excel file, it detects them as a 'Does not exist', even if both values are null in both documents that are compared. Is it supposed to do that, and is there a way to compare 2 null values, without them being included if values in both streams are null on the same field?