SQL for Backend Validation | Dataford Interview Questions

What is your experience with SQL for backend validation?

Using the provided orders and backend_validation_results tables, write a query that identifies records where backend data is missing, unexpectedly present, or differs from the stored order data. Treat two NULL values as equal.

Output

One row per validation failure, with order_id, db_status, backend_status, db_total, backend_total, and validation_result.
Exclude matching records.
Order by order_id ascending.

Schema

orders

Column	Type	Description
order_idPK	INT	Stored order identifier
status	VARCHAR(20)	Order status in the database
total_amount	NUMERIC(10,2)	Stored order total

backend_validation_results

Column	Type	Description
order_idPK	INT	Order identifier returned by the backend
status	VARCHAR(20)	Order status returned by the backend
total_amount	NUMERIC(10,2)	Order total returned by the backend

Your question is SQL for Backend Validation. Start with the requirements and the two tables in the Question tab.

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Problem