title: oracle systimestamp (sysdate) to milliseconds
body: <p>Could you provide implementation of stored function to get current <code>systimestamp</code> as milliseconds.<br>
  Something I can use like</p>
  
  <pre><code>select current_time_ms from dual;
  </code></pre>
  
  <p>and get the difference, measured in milliseconds, between the current time and midnight, January 1, 1970 UTC.</p>
  
  <p>Thanks.</p>