将会话更改为电子邮件会话

this session is about the username, and i want to make a session for an email, i tryd soo much but everything i try, doesnt work. Can someone help me to make a new session for email

<?php

session_start();
header('Content-type: text/html;charset=UTF-8');
if(!isset ($_SESSION['username']) and isset($_COOKIE['username'], $_COOKIE['password']))
{
    $cnn = mysql_query('select password,id from users where username="'.mysql_real_escape_string($_COOKIE['username']).'"');
    $dn_cnn = mysql_fetch_array($cnn);
    if(sha1($dn_cnn['password'])==$_COOKIE['password'] and mysql_num_rows($cnn)>0)
    {
        $_SESSION['username'] = $_COOKIE['username'];
        $_SESSION['userid'] = $dn_cnn['id'];
    }
}
?>
<?php

echo htmlentities($_SESSION['username']); 

?>

Thanks everyone for helping!

I did just a few second ago and it works perfectly!

**

yes!

session_start();
header('Content-type: text/html;charset=UTF-8');
if(!isset($_SESSION['username']) and isset($_COOKIE['username'], $_COOKIE     ['email']))
 {
  $cnn = mysql_query('select email, from users where              username="'.mysql_real_escape_string($_COOKIE['username']).'"');  $dn_cnn = mysql_fetch_array($cnn);
if(sha1($dn_cnn['email'])==$_COOKIE['email'] and mysql_num_rows($cnn)>0)
{
    $_SESSION['username'] = $_COOKIE['username'];
    $_SESSION['userid'] = $dn_cnn['email'];
}
 }
 ?>
 <?php

 echo htmlentities($_SESSION['userid']); 

?>

now i get as id 1 :( i dont want that id :P **

You can do this way,

session_start();
header('Content-type: text/html;charset=UTF-8');
if(!isset ($_SESSION['username']) and isset($_COOKIE['username'],$_COOKIE['password']))
{
   $cnn = mysql_query('SELECT password,id,email from users where username="'.mysql_real_escape_string($_COOKIE['username']).'"');
   $dn_cnn = mysql_fetch_array($cnn);
   if(sha1($dn_cnn['password'])==$_COOKIE['password'] and mysql_num_rows($cnn)>0)
   {
    //$_SESSION['username'] = $_COOKIE['username'];
    $_SESSION['userid'] = $dn_cnn['id'];
    $_SESSION['email'] =  $dn_cnn['email'];
    }
}

This should set the session as an email. But remember you have to select email field from the users table if there is any email field that exists.