title: How to subtract 2 dates in oracle to get the result in hour and minute
body: <p>I want to subtract 2 dates and represent the result in hour and minute in one decimal figure.</p>
  
  <p>I have the following table and I am doing it in this way but the result is not as desired.</p>
  
  <p>There is some slight variation, I'm sure this is simple arithmetic but I'm not getting it right.    </p>
  
  <pre><code>select start_time, end_time, (end_time-start_time)*24 from 
  come_leav;    
  </code></pre>
  
  <pre>
  
  START_TIME          END_TIME            (END_TIME-START_TIME)*24    
  ------------------- ------------------- ------------------------      
  21-06-2011 14:00:00 21-06-2011 16:55:00  2.9166667      
  21-06-2011 07:00:00 21-06-2011 16:50:00  9.8333333      
  21-06-2011 07:20:00 21-06-2011 16:30:00  9.1666667      
  
  </pre> 
  
  <p>I want the result (end_time-start_time) as below.    </p>
  
  <pre>
  16:55- 14:00 = 2.55      
  16:50-07:00 = 9.5      
  16:30-7:20 = 9.1 and so on.    
  </pre>
  
  <p>How can I do that?</p>