Returns true when there’s only one value in the specified column.
The column to check the filter info.
TRUE when the context for ColumnName has been filtered down to one distinct value only. Otherwise is FALSE.
HASONEVALUE corresponds to the following code:
COUNTROWS ( VALUES ( <ColumnName> ) ) = 1
Learn more about HASONEVALUE in the following articles:
Using the SELECTEDVALUE function in DAX
This article describes how the SELECTEDVALUE DAX function simplifies the syntax required in many scenarios where you need to read a single value selected in the filter context. » Read more
Distinguishing HASONEVALUE from ISINSCOPE
This article describes the differences between HASONEVALUE and ISINSCOPE, which are two useful DAX functions to control the filters and the grouping that are active in a report. » Read more
Other related functions are:
Contributors: Alberto Ferrari, Marco Russo
MSDN documentation: https://docs.microsoft.com/en-us/dax/hasonevalue-function-dax