Hello!  How are you!  Can you provide me with a list of all patient names?
select name from patient
Thank you so much!  Can you filter this list to show only the patients who had more than one appointment?
select name from appointment as t1 join patient as t2 on t1.patient = t2.ssn group by t1.patient having count ( * ) > 1
Great! Can you update this list to include the phone number of each of these patients?
select name, phone from appointment as t1 join patient as t2 on t1.patient = t2.ssn group by t1.patient having count ( * ) > 1