Creating a Query with Data from 4 Tables.

Question

Hey guys. I'm having a small problem figuring out the best way for me to handle this query.
I'm trying to make a query which outputs the amount of appointments a GP has furfilled, and the total amount allowed.
I have 4 tables, for each I'm just gonna list the relevent columns:
Appointment: ID, Patient_ID.
Patient: ID, GP_ID.
GP: ID, Trust_ID.
Trust: ID, Quota.
Appointment table has 400 entries (2 per patient atm).
Patient table has 200 entries.
GP Table has 30 entries (GP's can be assigned to more than one person) .
Trust table has 6 entries.
What I need to do is, look at the appointment table and get the number of times each patient has an appointment.
Go through the patient table, and find out which GP the patient in the appointment belongs to.
Add each occurance to the correct GP.
Find out which Trust each GP belongs to, and add the total for each GP to the correct Trust.
Check the quota in the Trust table, to see if the total is more than the allowed.
I can't seem to think of an easy or simple way for me to do this. Can anyone help please? Many thanks.

Answer 1

Hi,
That sounds like a job for JOIN.
To check the quotas against the total, use the SUM function; either the aggregate SUM or the analytic SUM, depending on your requirements.
Sorry this answer is so vague, but that's the bes I can do with the information provided so far.
Whenever you have a problem, please post a little sample data (CREATE TABLE and INSERT statements, relevant columns only) from all tables involved. In this case, between 2 and 10 rows of data per table should be enough to show what you need to do.
Also post the results you want from that data, and an explanation of how you get those results from that data, with specific examples.
Always say which version of Oracle you're using.