Hello

I created this function to update the uread row (longtext) with login.
Everything works fine, however, I would like to update the row wihout loading all data from the uread field...
PHP Code:
function update(){
  global 
$mid//message id from the forum table
  
$mid = (int) $mid;
  
$login=$_SESSION['login'];
  
$rd mysql_query("SELECT uread FROM forum WHERE mid=$mid") or die(mysql_error());
  
$rdrow=mysql_fetch_array($rd);
  
$us=$rdrow['uread']; //get all data from the row
  
$rdd mysql_query("SELECT uread FROM forum WHERE uread LIKE '%$login%' AND mid=$mid") or die(mysql_error()); //query the row
  
if(mysql_num_rows($rdd) ==0){ //if result ==0
  
return mysql_query("UPDATE forum SET uread = '$us $login' WHERE mid=$mid") or die(mysql_error()); //update row and set the login where message id
  
}
  return 
false;

my question:

How can I insert the login in the uread field without loading all data from the row?

Thanks