Rolling 7-Day Sales Trends | Dataford Interview Questions

How would you use SQL window functions to calculate rolling 7-day sales trends by product and region for W.W. Grainger?

Write a PostgreSQL query using the provided sales, products, and regions data. Include dates with sales activity, calculate daily sales, and calculate the total for the current date plus the preceding six calendar days.

Output

One row per product, region, and sales date with activity.
Columns: product_name, region_name, sales_date, daily_sales, and rolling_7_day_sales.
Sort by product_name, region_name, and sales_date ascending.

Schema

sales

Column	Type	Description
sale_idPK	INT	Unique sales transaction identifier
product_id	INT	Product associated with the sale
region_id	INT	Sales region associated with the transaction
sales_date	DATE	Date of the sale
sales_amount	NUMERIC(12,2)	Sales amount for the transaction

products

Column	Type	Description
product_idPK	INT	Unique product identifier
product_name	VARCHAR(100)	Grainger product name

regions

Column	Type	Description
region_idPK	INT	Unique region identifier
region_name	VARCHAR(100)	Sales region name

Your question is Rolling 7-Day Sales Trends. Start with the requirements and the three tables in the Question tab.

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Problem