Top Transaction Users by Country | Dataford Interview Questions

FinEdge wants to identify its highest-volume users in each country based on transaction activity. Write a PostgreSQL query to return the top 3 users per country by total transaction volume.

Requirements

Join users and transactions.
Calculate each user's total transaction volume per country using the sum of amount.
Exclude transactions where amount is NULL.
Return the top 3 users within each country using a window function.
Order the final output by country, then rank, then user_id.

Schema

users

Column	Type	Description
user_idPK	INT	Unique identifier for each user
user_name	VARCHAR(100)	User display name
country	VARCHAR(50)	Country associated with the user
signup_date	DATE	Date the user signed up

transactions

Column	Type	Description
transaction_idPK	INT	Unique identifier for each transaction
user_id	INT	User who made the transaction
amount	DECIMAL(10,2)	Transaction amount
transaction_date	DATE	Date of the transaction

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