Patients Multiple Appointments

SELECT 
  p.patient_id, 
  p.first_name, 
  p.last_name, 
  COUNT(a.appointment_id) AS total_appointments
FROM patients p
JOIN appointments a ON p.patient_id = a.patient_id
GROUP BY p.patient_id, p.first_name, p.last_name
HAVING COUNT(a.appointment_id) > 3;

Talk about how you're using a JOIN to connect patients to their appointments, then grouping the results to count how many appointments each patient had. Use HAVING to filter for those with more than three. This kind of query helps track highly engaged or frequent patients.