solve THE TEASER: retrieving the largest value from mysql db

[navajes123]

friends! good morning...can u solve this small problem of mine?
wat i want is to find out the largest of the int values stored in a field called 'qno' in the table 'questions'. i tried the following script....but i dont get any output.....kindly help......waiting eagerly

<?php
/* Connect to the MySQL database */
$db_connectio = mysql_connect( )
or die("Could not connect to DB");

/* Select the MasteringPHP database */
mysql_select_db ("questionnaire", $db_connectio)or die("mysql_error()");

$query15="select max(qno) from questions";
$result15=@mysql_query($query15,$db_connectio) or die(mysql_error());
   while( $row=@mysql_fetch_object($result15))

      { $up_lim=$row->qno;}

   echo$up_lim;
   
   mysql_close();
   ?>

[tombell]

<?php 
/* Connect to the MySQL database */ 
$db_connectio = mysql_connect( ) 
or die("Could not connect to DB"); 

/* Select the MasteringPHP database */ 
mysql_select_db ("questionnaire", $db_connectio)or die("mysql_error()"); 

$query15="select max(qno) AS maximum from questions"; 
$result15=@mysql_query($query15,$db_connectio) or die(mysql_error()); 
   while( $row=@mysql_fetch_object($result15)) 

      { $up_lim=$row->maximum;} 

   echo$up_lim; 
    
   mysql_close(); 
   ?>