comparing two columns revisited

[JoeM]

Now I need to find a way to show data in 3 columns. The first column has id
#s and the second is a sub category of that. The third column is a shorter
list of duplicates of the second. I need to show which are duplicates and
what Id they are under.

 

[Glenn]

Now I need to find a way to show data in 3 columns. The first column has id
#s and the second is a sub category of that. The third column is a shorter
list of duplicates of the second. I need to show which are duplicates and
what Id they are under.

Maybe a brief example would make this clearer?