Top-N Products With Window Functions | Dataford Interview Questions

DICK'S Sporting Goods wants a quick view of its strongest recent product sales. Using the product_sales table, write a PostgreSQL query that finds the three products with the highest total units sold during the inclusive 30-day period from January 17, 2025 through February 15, 2025.

Requirements

Exclude rows outside the 30-day period and rows with missing product, category, or unit values.
Aggregate units by product and category, then return the top three products ordered by total units sold descending.

Schema

product_sales

Column	Type	Description
sale_idPK	INT	Unique sale identifier
product_name	VARCHAR(100)	Product sold through DICK'S Sporting Goods
category	VARCHAR(50)	Product category
sale_date	DATE	Date on which the sale occurred
units_sold	INT	Number of units sold

Your question is Top-N Products With Window Functions. 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

Requirements

Exclude rows outside the 30-day period and rows with missing product, category, or unit values.
Aggregate units by product and category, then return the top three products ordered by total units sold descending.

Schema

product_sales

Column	Type	Description
sale_idPK	INT	Unique sale identifier
product_name	VARCHAR(100)	Product sold through DICK'S Sporting Goods
category	VARCHAR(50)	Product category
sale_date	DATE	Date on which the sale occurred
units_sold	INT	Number of units sold

Your question is Top-N Products With Window Functions. 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.