How do you evaluate if there is 2 discs or not I'm under Rename?

I have an action to rename mp3s. And I am not sure how to evaluate if the %discnumber% tag. Is empty, or has greater than 1.

So I can add: Disc 01, Disc 02, Disc 03, etc. But only if the second value in the tag is above 1. Like: 1/2 or 2/2 or 1/3, disc number/total discs

If that tag is empty I don't want it to add a disc number and if that tag is 1 or 1/1 I don't want it to add a disc number. I'm not sure how I would add that to an action rename script to go with the rest of host I have it renaming/organizing it.

As the first step you should isolate the total disc number from the compound disc number.
Action: Guess values
Source format: %discnumber%
Guessing pattern: %dummy%/%disctotal%
Now use the tagfield DISCTOTAL for the other calculations.

DD.20160622.0902.CEST

I would clear those discnumber fields first that apparently have no decent contents.

The square brackets in a format string serve as "if" operator.
So %album%[ - %discnumber%]
would lead to
The Lamb lies down on broadway - 1
if %discnumber% is 1
and to
Abacab
if discnumber is not filled.

Perhaps this is what you are looking for.

Thanks to both of you, I actually was able to get it to work with this (In Case anyone else needs to get it working):
$if($grtr($right(%discnumber%,1),1),Disc 0$num(%discnumber%,1) - ,)