Aggregate Distinct Diagnoses per Patient

Postgres Engine
Database Schema
Question (#23)
Display (patient_id, diagnosis) for the two patients with IDs 5 and 11. List all distinct diagnoses of each of these patients, with the diagnoses of each patient collected into a single row.
Expected Output
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Databases & Questions
Hint
Aggregate per patient, and make sure repeated diagnoses appear only once inside the string.
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