SQL & PL/SQL

Hi again,

3rd post today, just a quick one this time.

I need to write a query which identifies a list of employees from the employee table who have violated a set of given rules:

Rule 1. MOST EXPENSIVE CAR:

/Can be borrowed by: MANAGERS/SALES REP/HIGHEST EARNING EMPLOYEE IN EACH LOCATION.
/Car must be returned on the day it was borrowed.

Rule 2. LEAST EXPENSIVE CAR:

/Can be borrowed by: MANAGERS/SALES REP/HIGHEST EARNING EMPLOYEE IN EACH LOCATION

Rule 3. ALL OTHER CARS:

/Can be borrowed by: MANAGERS/SALES REPS WHO HAVE SOLD > £30000 OF GOODS.

I'm guessing I would use a case statement, have already built queries to find 1)Most expensive car 2) Least expensive car 3) Sales Reps earning over £30000.
I am just not sure of how to build tables based on information from 3/4 different tables.
Have literally just moved over to SQL developer after years of using MSAccess, annoying thing is I could do this in seconds with the access visual query editor..

Any help would be much appreciated. If any more info is needed please let me know.

Thanks.