sql-mkh4

DROP TEMPORARY TABLE IF EXISTS patient_visits;
CREATE TEMPORARY TABLE patient_visits LIKE patients;
INSERT INTO patient_visits
SELECT *
FROM patients
WHERE id
IN (
  SELECT patient_id
  FROM patient_histories
  GROUP BY patient_id
  HAVING COUNT(patient_id) = 1
);
select * from patient_visits join patient_histories
on patient_visits.id = patient_histories.patient_id
where patient_histories.year="2076"
and patient_histories.month="8"
and patient_histories.day="19"