title: Getting seconds between two Oracle Timestamps
body: <p>Tom Kyte <a href="http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:10729709873260" rel="noreferrer">suggests</a> to use <a href="http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/functions050.htm" rel="noreferrer"><code>EXTRACT</code></a> to get the difference:</p>
  
  <pre><code>extract( day from (x-y) )*24*60*60+
  extract( hour from (x-y) )*60*60+
  ...
  </code></pre>
  
  <p>This seems to be harder to read and slower than this, for example:</p>
  
  <pre><code>( CAST( x AS DATE ) - CAST( y AS DATE ) ) * 86400
  </code></pre>
  
  <hr>
  
  <p>So, what is the way to get the difference between two Timestamps in seconds? Thanks!</p>