SQL for Requirement Validation | Dataford Interview Questions

Write SQL to validate system requirements by comparing data across tables and identifying mismatches.

Compare the expected requirement values with the observed system values, including records missing from either table and NULL values.

Output

Return one row per discrepancy with requirement_id, requirement_name, expected_value, observed_value, and mismatch_type.
Include missing, unexpected, and differing values, but exclude matching records.
Order by requirement_id ascending.

system_requirements

Column	Type	Description
requirement_idPK	INT	Unique identifier for the system requirement
requirement_name	VARCHAR(100)	Name of the requirement
expected_value	VARCHAR(100)	Value required by the specification

validation_results

Column	Type	Description
requirement_idPK	INT	Identifier of the validated requirement
observed_value	VARCHAR(100)	Value observed in the system
validation_status	VARCHAR(20)	Recorded validation status

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

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