SQL Joins for Patient Data | Dataford Interview Questions

Write a SQL query using different types of joins (inner, left, right, full) to combine patient and prescription records.

Use the provided patients and prescriptions tables. Return a single result that identifies which join produced each row and preserves matched and unmatched records.

Output

Columns: join_type, patient_id, patient_name, prescription_id, medication_name
Include results from all four join types, with one row per joined record
Sort by join_type, then patient_id, then prescription_id, placing NULL identifiers last.

Schema

patients

Column	Type	Description
patient_idPK	INT	Unique patient identifier
patient_name	VARCHAR(100)	Patient full name

prescriptions

Column	Type	Description
prescription_idPK	INT	Unique prescription identifier
patient_id	INT	Patient associated with the prescription
medication_name	VARCHAR(100)	Prescribed medication name

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Problem