title: PostgreSQL search criteria must output missing row
body: <p>I have two postgreSQL tables, namely: <strong>employees</strong> and <strong>employee_cars</strong>.
  I need to output all employees that own a 'BMW', 'MERC' AND 'VW', BUT NOT an 'AUDI'.</p>
  
  <p>I have tried below query:</p>
  
  <pre><code>SELECT DISTINCT a.employee_name, b.car_brand
  FROM employees a
  LEFT JOIN employee_cars b 
  ON a.employee_id = b.employee_id
  WHERE b.car_brand IN ('BMW','MERC','VW')
  AND b.car_brand NOT LIKE 'AUDI';
  </code></pre>
  
  <p>OUTPUT below:</p>
  
  <pre><code>employee_name,car_brand
  "Mary","BMW"
  "Mary","MERC"
  "Mary","VW"
  "Paul","BMW"
  "Paul","MERC"
  "Paul","VW"
  </code></pre>
  
  <p>Problem is that each vehicle that an employee owns is a row in the employee_cars tables. So for example; I have 'Mary' which owns: 'BMW','MERC','VW','AUDI'.
  I have 'Paul' which only owns: 'BMW','MERC','VW'. 
  My query will display Both Mary and Paul, because they both own 'BMW','MERC','VW'. </p>
  
  <p>I only want to see 'Paul' in my results, because he is missing the 'AUDI'.</p>
  
  <p>Please note that I am not a DB expert, I will appreciate any help and assistance.
  Thanks in advance.</p>