This workflow automatically filters out all columns containing values that are all similar except for one row within that column. Note that missing values are not acknowledged as values, hence are not computed. The workflow may analyse almost all types of columns with a few exceptions such as images etc. There is no need to modify anything, unless the table you feed it with contains columns that you don't want to include in the filtering process. If that's the case, then you'll need to manually filter those columns in the first GroupBy Node.