This shows all promotional codes and all transactions. You can search by Order ID, Contact Name and other fields and see any promo codes that were applied.
You can also group by Promo Code:
And Generate Report, to get a CSV file that can be manipulated as desired.
Stats lets you see the overall results for each of the Promo Codes used in that account.
Choose a desired Date Range, or set a Custom Interval:
Use the SHOW button on any line to see all transactions that make up that selection: