7-Day Rolling Order Value SQL | Dataford Interview Questions

Write a SQL query using window functions to calculate each customer's 7-day rolling average order value.

Use the customers and orders tables. Include only orders with a matching customer and a non-null order date. The rolling period includes the order date and the six preceding calendar days. Null order values should not contribute to the average.

Output

One row per included order.
Columns: customer_id, customer_name, order_id, order_date, order_value, and rolling_avg_order_value.
Sort by customer_id, order_date, and order_id ascending.

Schema

customers

Column	Type	Description
customer_idPK	VARCHAR(10)	Unique customer identifier
customer_name	VARCHAR(100)	Customer display name

orders

Column	Type	Description
order_idPK	INT	Unique order identifier
customer_id	VARCHAR(10)	Customer who placed the order
order_date	DATE	Calendar date when the order was placed
order_value	NUMERIC(10,2)	Value of the order

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