We can use Selection of Discounts to input multiple discounts in the Discount Report. This would be a great way to compare a few discounts without pulling in all of our discounts. To create a Discount selection:
  1. Go to Analysis>Information Library>Add an Ad-hoc Query. Select the Discounts Source View.
  2. Here, we could use the query fields to pull the proper discounts we're looking for. To simply pull the names of the Discounts, we could add Name from the middle column to Include Records Where. Change Equal to into One Of, and then add all names of discounts we need.
  3. Preview the results to make sure our discounts have pulled in. If so, click the Set Save Options tab. 
  4. Name the Query, and then check the box that says, "Create a Selection?" After, click Save and Close.
Once we've created our selection, we'll need to apply this to our Discount Report. 
  1. Go to Sales and click Discount under Reports.
  2. Where it says Discount, change All to say Selected Discounts.
  3. Use the magnifying glass to find our Discount Selection.
  4. Once the proper selection is filled in, change any other filters necessary, and then click View Report on the right.
We will now get a report on the usage numbers of these specific Discounts.