Running Sales Totals by Region | Dataford Interview Questions

Walmart Marketplace analysts need a regional view of recent sales performance. Using the reporting date of 2025-03-15, write a PostgreSQL query that calculates daily sales and a running 30-day total for each region.

Requirements

Include sales from 2025-02-14 through 2025-03-15, inclusive.
Exclude rows with a missing region.
Aggregate multiple sales records on the same region and date into daily sales.
Use a window function to calculate the cumulative sales total independently for each region, ordered by sale date.

Schema

marketplace_sales

Column	Type	Description
sale_idPK	INT	Unique sale identifier
region	VARCHAR(50)	Walmart Marketplace sales region
sale_date	DATE	Date when the sale occurred
sales_amount	NUMERIC(12,2)	Sale amount in dollars

Your question is Running Sales Totals by Region. 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

Include sales from 2025-02-14 through 2025-03-15, inclusive.
Exclude rows with a missing region.
Aggregate multiple sales records on the same region and date into daily sales.
Use a window function to calculate the cumulative sales total independently for each region, ordered by sale date.

Schema

marketplace_sales

Column	Type	Description
sale_idPK	INT	Unique sale identifier
region	VARCHAR(50)	Walmart Marketplace sales region
sale_date	DATE	Date when the sale occurred
sales_amount	NUMERIC(12,2)	Sale amount in dollars

Your question is Running Sales Totals by Region. 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.