"No column in spec compatible to "NominalValue"" error message while trying to make a chart

Hello,

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!

Hi @saturn and welcome to the forum.

Here’s an example workflow that demonstrates a couple of ways you could do this. Note that in one method a GroupBy node isn’t required at all - you let the Pie/Donut Chart node do the aggregation itself.

Simple_PieChart_Example.knwf (16.6 KB)

2021-01-28 12_30_59-KNIME Analytics Platform

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I didn’t even think of the second method but both worked perfectly! Thank you!

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