Let’s give this a shot:
TryCatchColumnAppendExample.knwf (34.0 KB)
I tried to document the nodes so that it’s clear what they do. I did use a bit of flow variables that maybe aren’t as clear, so let me know if you have questions about how it works.
Basically we use a dummy table to populate when there is a failure in the Category to Number node. We then take the name of the failed column and append it with a “failed_” signifier, so that we can split our columns in the end and easily identify which ones didn’t work.