errore mysql, setcookie, header

[98edoardo]

ti ringrazio mi è bastato utilizzarlo come un array... ma ora ho un'altro problema, mysql i_num_rows restituisce 0 anche quando c'è uno o più record nel database...

$graph = $facebook -> api('/me','GET');                       
$firstname = $graph['first_name'];           
$lastname = $graph['last_name'];          
$mail = $graph['email'];            
$uid = $graph['id'];            
$birthday = strtotime($graph['birthday']);            
$fb_profile = $graph['link'];            
$username = $graph['username'];            
$username_verified = 0;            
$register_date = time();           
            
 if($query = $mysqli -> query("SELECT * FROM utenti WHERE uid='$uid'")) {                
if(mysqli_num_rows($query) == 0) {                    
echo mysqli_num_rows($query);                   
 if($query2 = $mysqli -> query("INSERT INTO utenti (uid, nome, cognome, email, data, fb_profile, username, username_verified, data_reg) VALUES ('$uid', '$firstname', '$lastname', '$mail', '$birthday', '$fb_profile', '$username', '$username_verified', '$register_date')")) {                       
 if($query3 = $mysqli -> query("SELECT * FROM utenti WHERE uid='$uid'")) {                            
$row1 = $query3 -> fetch_array(MYSQLI_ASSOC);                            
setcookie("id", $row1['id'], time()+31536000);                           
 //header("location: /");                        
} else {                           
 echo $mysqli -> error;                        
}                    
} else {                        
echo $mysqli -> error;                   
 }               
 } else {                   
 $row = $query -> fetch_array(MYSQLI_ASSOC);                    
setcookie("id", $row['id'], time()+31536000);                    
header("location: /");                
}            
} else {                
echo $mysqli -> error;            
}