Top 10 Customers by Volume | Dataford Interview Questions

Your question is Top 10 Customers by Volume. Start with the requirements and the two tables on the right.

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Problem

Chase analytics needs a customer-level view of transaction volume for reporting in the Chase mobile app. Write a PostgreSQL query that identifies the 10 customers with the highest total value of completed transactions.

Requirements

Join customers to transactions using customer_id.
Include only transactions whose status is COMPLETED.
Calculate total transaction volume with SUM(transaction_amount) for each customer.
Return the top 10 customers, ordered by total volume descending and customer ID ascending to make ties deterministic.

Schema

customers

Column	Type	Description
customer_idPK	INT	Unique Chase customer identifier
customer_name	VARCHAR(100)	Customer display name
customer_segment	VARCHAR(30)	Optional customer segment

transactions

Column	Type	Description
transaction_idPK	INT	Unique transaction identifier
customer_id	INT	Customer associated with the transaction
transaction_amount	NUMERIC(12,2)	Monetary value of the transaction
transaction_date	DATE	Date the transaction occurred
status	VARCHAR(20)	Transaction processing status