var g_oHtmlEncodeElement;

function htmlEscape(text)
{
    g_oHtmlEncodeElement = g_oHtmlEncodeElement || document.createElement("div");
    g_oHtmlEncodeElement.innerText = g_oHtmlEncodeElement.textContent = text;
    return g_oHtmlEncodeElement.innerHTML;
}

function htmlUnescape(html)
{
    g_oHtmlEncodeElement = g_oHtmlEncodeElement || document.createElement("div");
    g_oHtmlEncodeElement.textContent = g_oHtmlEncodeElement.innerText = "";
    g_oHtmlEncodeElement.innerHTML = html;
    return g_oHtmlEncodeElement.innerText || g_oHtmlEncodeElement.textContent;
}

declare
  diff interval day to second :=
        cast('18-DEC-08 11.00.00 PM' as timestamp) - cast('18-DEC-08 9.59.58.5 PM' as timestamp);
  secs number;
begin
  select
    extract(day from diff) * 86400
    + extract(hour from diff) * 3600
    + extract(minute from diff) * 60
    + extract(second from diff)
 into
  secs
  from dual;
 dbms_output.put_line(secs);
end;