Top 10 Users by Volume | Dataford Interview Questions

Write a SQL query to find the top 10 users by transaction volume for NinjaHoldings. Treat transaction volume as the sum of transaction amounts. Use the users and transactions tables, include only users with at least one transaction, and handle nullable amounts as zero.

Output

One row per qualifying user with user_id, user_name, and total_transaction_volume
Return at most 10 users, ordered by total volume descending, then user_id ascending to break ties

Schema

users

Column	Type	Description
user_idPK	INT	Unique NinjaHoldings user identifier
user_name	VARCHAR(100)	Display name of the user

transactions

Column	Type	Description
transaction_idPK	INT	Unique transaction identifier
user_id	INT	User associated with the transaction
amount	DECIMAL(12,2)	Transaction amount

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