title: Logic of a SQL Query
body: <p>My Query does not work logically. I am trying to get a list of students who studied any AutoCAD course who has not studied any Revit Course. My Query is structured like this:</p>
  
  <pre><code>Select * From StudentData 
  Where (CourseName LIKE 'AutoCAD%') 
  AND NOT EXISTS (Select * From StudentData Where (CourseName LIKE 'Revit%'));
  </code></pre>
  
  <p>Doing the inverse of the EXISTS does give me a list of who studied both AutoCAD + Revit, but the NOT does not return any value.</p>
  
  <p>Any Ideas?</p>