Top 5 Customers by Purchase Frequency | Dataford Interview Questions

Wurth Louis & needs to identify its most frequent customers for the 2024 purchasing year. Write a PostgreSQL query using the sales_orders table to return the top five customers by number of orders placed between 2024-01-01 and 2024-12-31.

Assume the reporting date is 2025-01-01, so the previous year is defined as 2025-01-01 - INTERVAL '1 year' through, but not including, 2025-01-01.

Requirements

Count orders for each customer within the one-year period.
Return the five highest-frequency customers, ordering by order count descending and customer name ascending to break ties.

Schema

sales_orders

Column	Type	Description
order_idPK	INTEGER	Unique sales order identifier
customer_name	VARCHAR(100)	Name of the Wurth Louis customer
order_date	DATE	Date on which the order was placed

Your question is Top 5 Customers by Purchase Frequency. Start with the requirements and the one table 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

Assume the reporting date is 2025-01-01, so the previous year is defined as 2025-01-01 - INTERVAL '1 year' through, but not including, 2025-01-01.

Requirements

Count orders for each customer within the one-year period.
Return the five highest-frequency customers, ordering by order count descending and customer name ascending to break ties.

Schema

sales_orders

Column	Type	Description
order_idPK	INTEGER	Unique sales order identifier
customer_name	VARCHAR(100)	Name of the Wurth Louis customer
order_date	DATE	Date on which the order was placed

Your question is Top 5 Customers by Purchase Frequency. Start with the requirements and the one table 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.