Elias here with Shopify Support. That's a great question!
There is a Discount report in the Finance Summary of the Reports (Analytics > Reports), which can show every order with a discount. However, if you're trying to pull a report for sales with a specific discount code, you can filter your orders by searching the discount code directly on the Orders page. After that, you can export the list of orders containing the discount code.
Alternatively, there are also third-party reporting apps that can pull a sales reports based on a specific discount code. I'd recommend using DeepMine, as they can create custom reports based on discounts and they offer a 60-day free trial. If you need any help with this app, you can always reach out to the developer through the contact information found in the Support Section of their app's page.
I hope this provides a couple of solutions for you! If you have any other questions on this topic, don't hesitate to let me know!