Re: Help with trigger

[laptop alias]

Generally, it's a bad idea to store the same thing twice!

SELECT p.*
     , MAX(a.date_of_appointment) date_of_last_appointment
  FROM patients p
  JOIN appointment a
    ON a.patient_id = p.patient_id
   AND a.status {[=/!=/IN] (something)}/{IS NOT NULL} 
 GROUP
    BY patient_id;

You can store this query as a VIEW