Customers With No Recent Orders | Dataford Interview Questions

Vanguard Personal Investor wants to identify customers who may need re-engagement. Using the customer and order data below, write a PostgreSQL query that finds every customer who has not placed an order during the six-month period ending on 2026-08-29.

Requirements

Return every qualifying customer, including customers who have never placed an order.
Include the customer ID, customer name, and their most recent order date across all available history.
Treat an order with a NULL order date as not occurring within the six-month period.
Sort the output alphabetically by customer name, then by customer ID.

Schema

customers

Column	Type	Description
customer_idPK	INTEGER	Unique Vanguard customer identifier
customer_name	VARCHAR(100)	Customer's full name
joined_date	DATE	Date the customer joined Vanguard Personal Investor

orders

Column	Type	Description
order_idPK	INTEGER	Unique order identifier
customer_id	INTEGER	Customer who placed the order
order_date	DATE	Date the order was placed
order_status	VARCHAR(20)	Current order status

Your question is Customers With No Recent Orders. Start with the requirements and the two tables in the Question tab.

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Problem