We can accomplish this task by creating a discount query and outputting the username that created the discount
  1. Click Analysis > information library > add an ad hoc query
  2. Change the record type to Discount > click on the Discounts source view > click OK
  3. Drag name from the results fields to display section to the include records where section
  4. Enter the name of the discount and click OK
  5. In the middle column scroll down until you find the added by username field
  6. Drag that field to the results fields to display section
  7. Click preview results