Window Functions vs Group By | Dataford Interview Questions

Explain the difference between a window function and a group by clause.

Use the provided sales data to demonstrate both approaches for department-level totals and row counts. Return the detail rows along with the equivalent department metrics calculated by each approach.

Output

One row per sale, ordered by department, then sale_id.
Include sale_id, department, employee_name, amount, department totals from both approaches, and department row counts from both approaches.

Schema

sales

Column	Type	Description
sale_idPK	INT	Unique identifier for the sale
department	VARCHAR(50)	Department responsible for the sale
employee_name	VARCHAR(100)	Employee associated with the sale
amount	NUMERIC(10,2)	Sale amount

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