I have build a visualization using the lookup function to find the values for the previous month as attached.
To color this column last i.e. Change i have created a if condition but it is doing it is changing all columns based on the condition.
How would it only change for only the desired last column. I tried searching but did not find answer that could assist.
I believe this article may offer a solution for you: Applying Color to a Single Column in a Crosstab View | Tableau Software
It provide 3 options on how to apply color to a single column within a crosstab.
Hope this helps!