Foreign Keys vs Joins | Dataford Interview Questions

Foreign keys versus joins and their advantages.

Asked in the technical 1 stage. Use the tables below to identify order rows that have a valid customer reference.

Output

One row per valid order, with columns order_id, customer_id, customer_name, and order_status
Include only orders whose customer_id matches an existing customer
Sort by order_id ascending

customers

orders

Column	Type	Description
order_idPK	INT	Unique order identifier
customer_id	INT	Customer reference from customers.customer_id
order_status	VARCHAR(20)	Current order status
order_amount	NUMERIC(10,2)	Order amount

Your question is Foreign Keys vs Joins. Start with the requirements and the two tables in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Foreign keys versus joins and their advantages.

Asked in the technical 1 stage. Use the tables below to identify order rows that have a valid customer reference.

One row per valid order, with columns order_id, customer_id, customer_name, and order_status
Include only orders whose customer_id matches an existing customer
Sort by order_id ascending

customers

orders

Column	Type	Description
order_idPK	INT	Unique order identifier
customer_id	INT	Customer reference from customers.customer_id
order_status	VARCHAR(20)	Current order status
order_amount	NUMERIC(10,2)	Order amount

Your question is Foreign Keys vs Joins. Start with the requirements and the two tables in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.