Well.
Here is the workflow to do this:
After the “One to Many” node we have a “Column List Loop Start” to loop over each year column and a “Column Expressions” to assign the value “New/Existing”. After the loop end we have a “Column Filter” node to exclude the duplicates of the first 3 columns(using regex).
Please let me know if this is what you need:
oneToMany.knwf (28.4 KB)
Best,
Armin
P.S. To have the year columns in order, you can use a “Sorter” node to sort rows based on the “purchase year” and then a “Domain Calculator” node (for the same column) just before the “One to Many” node.