SQL Join Sales and Customers | Dataford Interview Questions

Given these two tables (Sales and Customers), write a SQL query to find the top 5 regions by revenue in the last quarter.

Assume the last quarter is October 1, 2025 through December 31, 2025. Exclude sales without a matching customer or region, and use total sale revenue for ranking.

Output

One row per region with columns region and total_revenue
Include the five highest-revenue regions only
Order by total_revenue descending, breaking ties by region ascending

Schema

sales

Column	Type	Description
sale_idPK	INT	Unique identifier for the sale
customer_id	INT	Customer associated with the sale
sale_date	DATE	Date when the sale occurred
revenue	NUMERIC(12,2)	Revenue generated by the sale

customers

Column	Type	Description
customer_idPK	INT	Unique identifier for the customer
customer_name	VARCHAR(100)	Customer or account name
region	VARCHAR(50)	Sales region assigned to the customer

Your question is SQL Join Sales and Customers. Start with the requirements and the two tables in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem