I recently started using KNIME so I apologize in advance if this is a very “easy” problem. My goal is to get a pie chart showing the amount of existent and missing values of a column.
In my example I have a table with a column including different brands. Some fields in this column are empty. I took the groupby node and used manual aggregation on this column to 1) count the brands and 2) count the missing/empty fields. My result is a table with one row including two columns/two integers.
All I want to do is take these two numbers and get a pie chart out of it using the pie/donut chart node. But instead I get the error message: No column in spec compatible to “NominalValue”. I don’t really know what the error message means or what to do to fix it. It shouldn’t be too complicated to make a pie chart out of two numbers, right?
I’m very thankful for hints and solutions!