title: Add Seconds to Timestamp from another Timestamp
body: <p>I got two timestamps:</p>
  
  <p>say:</p>
  
  <pre><code>21.10.2013 00:00:23
  </code></pre>
  
  <p>and</p>
  
  <pre><code>21.10.2013 00:00:00
  </code></pre>
  
  <p>How can I add the 23 Seconds from timestamp 1 to the second.</p>
  
  <p>My query is something like that at the moment:</p>
  
  <pre><code>select count(1) 
  from tbl where timestamp1 &gt;= NVL((select MAX(TIMESTAMP2) + ("Seconds from TS 1") 
  from tbl2), timestamp - 1);
  </code></pre>