Not able to fetch data from joomla 2.5 database

Question

Hi I am trying to fetch data from joomla session table based on session id. I am using code as under and able to get session id but when i am trying to get username based on bellow mentioned query i am not getting any output. So please help/guide me if there is problem in query. I had also check column name(if i mistype) with data table and those are correct.

session_start();
$_session_id=session_id();
echo "your session id is ".$_session_id;

$db = JFactory::getDBO();
$query = $db->getQuery(true);

//  $query = "SELECT username". " FROM izj5n_session"." WHERE session_id = $_session_id";

/*  $query->select('username');
    $query->from('izj5n_session');
    $query->where('session_id=$_session_id');*/

$query
    ->select('username')
    ->from('izj5n_session')
    ->where('session_id=$_session_id');

$db->setQuery($query);
$rows = $db->loadResult();
$itemrow = $rows;

print $itemrow;

Answer 1

defined( '_JEXEC' ) or die( 'Restricted access' );

jimport('joomla.filesystem.file');

JHtml::addIncludePath(JPATH_COMPONENT . '/helpers');

$db =& JFactory::getDBO();

$user =& JFactory::getUser();

echo $user->username

Answer 2

just guessing...

$query = "
SELECT username 
  FROM Izj5n_session
 WHERE session_id = $_session_id;
";