SQL for Business Insights | Dataford Interview Questions

Tell me about a time you used SQL to solve a business problem.

Support your answer with a representative PostgreSQL query using the supplied customer and order tables. Explain the business question, assumptions, validation steps, and how the result informed a decision.

Output

One row per qualifying customer.
Include customer_id, customer_name, completed_order_count, total_revenue, and latest_order_date.
Include completed orders from 2025-01-01 through 2025-03-31, customers with at least $100 in completed revenue, and sort by total revenue descending with customer ID as the tie-breaker.

Schema

customers

Column	Type	Description
customer_idPK	INT	Unique customer identifier
customer_name	VARCHAR(100)	Customer display name
segment	VARCHAR(30)	Optional customer segment

orders

Column	Type	Description
order_idPK	INT	Unique order identifier
customer_id	INT	Customer associated with the order
order_date	DATE	Date the order was placed
status	VARCHAR(20)	Order processing status
amount	NUMERIC(10,2)	Order revenue amount

Your question is SQL for Business Insights. 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