Returns a blank.
This expression has no parameters.
The BLANK value does not have a data type.
The BLANK value is automatically converted in case it is compared with other values.
The right way to check whether a value is BLANK is by using either the operator == or the ISBLANK function. Do not use the operator “=”.
The operator == is a “strictly equal to” operator that consider BLANK as a different value other than 0 or an empty string.
See related articles for more details.
Learn more about BLANK in the following articles:
How to handle BLANK in DAX measures
This article describes a counterintuitive behavior of BLANK in DAX measures affecting Power BI, Analysis Services, and Power Pivot. That behavior could cause mistakes in a report using alternate expressions of the same calculation. Indeed, these expressions are not equivalent when BLANK is involved. » Read more
Handling BLANK in DAX
The blank value in DAX is a special value requiring particular attention in comparisons. It is not like the special null value in SQL, and it could appear in any conversion from a table expression. This article explores in details the behavior of the blank value in DAX, highlighting a common error in DAX expressions […] » Read more
Contributors: Alberto Ferrari, Marco Russo, Kenneth Barber
MSDN documentation: https://docs.microsoft.com/en-us/dax/blank-function-dax