Display User That Is Does Not Exist in Other Table - sql

Question

I have query that I am supposed to display The number of patients a physician can take on. He can have no more than 5 patients at a time. I have this query working with the following:
select PHYSICIAN.PHYSICIAN_ID,PHYSICIAN.firstname_physician,PHYSICIAN.lastname_physician, phone.phone_number, 5-count(patient.patient_id) as "Numbers of new patients he/she can take"
from patient, physician, physician_phone, phone
where physician.physician_id = patient.physician_id and PHYSICIAN_PHONE.PHYSICIAN_ID = PHYSICIAN.PHYSICIAN_ID and phone.PHONE_ID = physician_phone.PHONE_ID
group by PHYSICIAN.PHYSICIAN_ID, PHYSICIAN.firstname_physician, PHYSICIAN.lastname_physician, physician_phone.phone_id, phone.phone_number
having count(patient.patient_id)<5;
However this only displays the physicians that have patients not the physicians who have 0 patients connected to them.
My attempt to display the physicians who also have 0 patients was the following:
select PHYSICIAN.PHYSICIAN_ID,PHYSICIAN.firstname_physician,PHYSICIAN.lastname_physician, phone.phone_number, 5-count(patient.patient_id) as "Numbers of new patients he/she can take"
from patient, physician, physician_phone, phone
where physician.physician_id = patient.physician_id and PHYSICIAN_PHONE.PHYSICIAN_ID = PHYSICIAN.PHYSICIAN_ID and phone.PHONE_ID = physician_phone.PHONE_ID
group by PHYSICIAN.PHYSICIAN_ID, PHYSICIAN.firstname_physician, PHYSICIAN.lastname_physician, physician_phone.phone_id, phone.phone_number
having count(patient.physician_id)<5 OR NOT EXISTS ( Select patient.physician_id from patient Where patient.physician_id != physician.physician_Id group by patient.physician_id)
Below are the table creates to help anyone better understand the relationship between the tables
Create Table Physician (
Physician_ID integer not null,
Firstname_physician Char(30Char) not null,
lastname_physician Char(30Char) not null,
Constraint Physician Primary Key (Physician_ID));
Create Table Patient (
Patient_ID integer not null,
Patient_FirstName Char(20Char) not null,
Patient_LastName Char(20Char) not null,
Patient_MI Char(1Char) not null,
Patient_Gender Char(15Char) not null,
Staff_id integer not null,
Physician_ID integer not null,
Constraint Patient_pk Primary Key (Patient_ID),
Constraint HomeCareStaff_fk Foreign Key (Staff_ID) References HomeCareStaff(Staff_id),
Constraint Physician_ID_fk10 Foreign Key (Physician_ID) References Physician(Physician_ID));
Both tables queries return the same exact thing. Please see image results of query
Hope this makes sense Here are also the inserts
--populating Physician table--
insert into Physician values (100, 'Sasia', 'Applebottom');
insert into Physician values (101, 'Mac', 'Cheese');
insert into Physician values (102, 'Mick', 'Donalds');
insert into Physician values (103, 'Saint', 'West');
insert into Physician values (104, 'Chicago', 'West');
insert into Physician values (105, 'Mason', 'Disic');
---Populate Patient Table
insert into Patient values (150, 'Hayley', 'Beachump', 'F', 'Female', 50, 100);
insert into Patient values (151, 'Jacob', 'Stutzmen', 'K', 'Male', 51, 100);
insert into Patient values (152, 'Christina', 'Smush', 'P', 'Female', 52, 100);
insert into Patient values (153, 'Doris', 'Dorphish', 'D', 'Female', 53,100);
insert into Patient values (154, 'Adam', 'Wang', 'M', 'Male', 54, 100);
insert into Patient values (155, 'Levina', 'Reinhart', 'U', 'Female', 55, 101);
insert into Patient values (156, 'Harper', 'Mosbey', 'M', 'Male', 56, 102);

Answer 1

You can use this
select PHYSICIAN.PHYSICIAN_ID, PHYSICIAN.firstname_physician, PHYSICIAN.lastname_physician, phone.phone_number, count(patient.patient_id) as "Numbers of new patients he/she can take"
from patient, physician, physician_phone, phone
where physician.physician_id = patient.physician_id and PHYSICIAN_PHONE.PHYSICIAN_ID = PHYSICIAN.PHYSICIAN_ID and phone.PHONE_ID = physician_phone.PHONE_ID
group by PHYSICIAN.PHYSICIAN_ID, PHYSICIAN.firstname_physician, PHYSICIAN.lastname_physician, physician_phone.phone_id, phone.phone_number
having count(patient.patient_id) = 0;