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SQL Window Ranking Patients
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SQL Window Ranking Patients

MediumSQL · PostgreSQL

Problem

Write a SQL query using window functions to rank patients by visit count within each clinic and return the top 3 per clinic.

Use the provided clinic, patient, and visit data. Return only patients with at least one visit.

Output

  1. One row per qualifying patient, with clinic_name, patient_id, patient_name, visit_count, and clinic_rank
  2. Include patients whose clinic rank is 1, 2, or 3; tied patients may produce more than three rows for a clinic
  3. Order by clinic name, rank ascending, then patient ID ascending

Schema

clinics
ColumnTypeDescription
clinic_idPKINTUnique clinic identifier
clinic_nameVARCHAR(100)Clinic name
patients
ColumnTypeDescription
patient_idPKINTUnique patient identifier
patient_nameVARCHAR(120)Patient full name
clinic_idINTAssigned clinic identifier
visits
ColumnTypeDescription
visit_idPKINTUnique visit identifier
patient_idINTPatient associated with the visit
clinic_idINTClinic where the visit occurred
visit_dateDATEDate of the visit
Tablesclinicspatientsvisits
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