foreach ($disArray as $a) {

        $query = "SELECT num FROM '".$tableName."' WHERE question='" .$a."'";
        $result = mysql_query($query, $this->conn) or die('Error: '.mysql_error());
        $row = mysql_fetch_array($result);
        //$row['num'] = $row['num'] + 1;

        $numb = $row['sayi'] + 1;

        $query = "UPDATE ".$tablename." SET `num`=".$numb."WHERE `question`=".$a.";
        mysql_query($query, $this->conn);
    }

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE question='Where are you from?'' at line 1

$query = "SELECT num FROM  '".$username."' WHERE question='" .$a."'";

""" <-- fuck