title: Add a timestamp to file name
body: <p>To avoid name collisions, I need to add a timestamp like extension to files my server creates.
  I was thinking to something like yyyymmddhhss.<br>
  <strong>What is the efficient way to generate a string like '201309091725'</strong> (with eventually more digits) ?<br>
  <code>select  cast( sysdatetime() as varchar)</code> does include spaces, colons and dots, making that unusable.</p>