title: How to select from a table where column not exists in another table
body: <p>table A  </p>
  
  <pre><code>id    city  
  1    koronadal  
  2    cebu  
  3    manila  
  </code></pre>
  
  <p>Table B  </p>
  
  <pre><code>id    city   
  1    cebu  
  </code></pre>
  
  <p>Expected ouput: </p>
  
  <pre><code>id    city
  1    koronadal  
  3    manila  
  </code></pre>
  
  <p>Here is my query:</p>
  
  <pre><code> Select a.id, a.city from tablea a left join tableb b on a.city = b.city
  </code></pre>
  
  <p>I get the wrong output.. please help me..</p>