Running Total Daily Sales | Dataford Interview Questions

Business Context

The DataAnnotation Store analytics team tracks completed sales across active store locations. They need a daily revenue report that also shows cumulative revenue within each region.

Task

Write a PostgreSQL query that calculates daily sales and a running total for each region.

Requirements

Include only completed sales with a non-null amount from active stores.
Aggregate sales by store region and sale date, combining multiple sales on the same day.
Use a window function to calculate the cumulative regional total in chronological order.
Return results ordered by region and sale date.

Schema

sales

Column	Type	Description
sale_idPK	INT	Unique sale identifier
store_id	INT	Store associated with the sale
sale_date	DATE	Date when the sale occurred
amount	NUMERIC(10,2)	Monetary value of the sale
status	VARCHAR(20)	Sale processing status

stores

Column	Type	Description
store_idPK	INT	Unique store identifier
store_name	VARCHAR(100)	Name of the store
region	VARCHAR(50)	Geographic sales region
is_active	BOOLEAN	Whether the store is active

Your question is Running Total Daily Sales. Start with the requirements and the two tables in the Question tab.

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Problem