title: SQL subquerying issue. Cannot further refine result of a query
body: <p>Say there is a set of tables: (all column names mean the same across all tables)</p>
  
  <ul>
  <li>movie_award { title, award, result(either "won" or "nominated") }</li>
  <li>writer { id, title }</li>
  <li>person { id, first_name, last_name }</li>
  </ul>
  
  <p>I cannot figure out an SQL query that: "Lists all writers who have written scripts ONLY for awarded movies.".</p>
  
  <p>So any writer that has written for a movie that did not win an award, even if the writer has had award winning movies are not included.</p>
  
  <p>Like the Venn diagram:</p>
  
  <p>writers w/ only un-awarded movies || writers with both || <strong>writers w/ only awarded movies</strong></p>
  
  <p>I can get as far as, not sure if on the right track:</p>
  
  <pre><code>SELECT DISTINCT p.first_name, p.last_name, w.title
  FROM writer w, person p, movie_award ma
  WHERE w.id = p.id AND w.title = ma.title AND ma.result = 'won'
  </code></pre>
  
  <p>However this only returns the writers and movies that have won an award at some time. It doesn't limit to writers which ALL of their movies have won awards.</p>
  
  <p>I'm open to different alternatives, ThankYou!!</p>