数据不会在mysql中更新

Question

我遇到的问题是它不会更新我的数据库。我无法检测到问题，甚至没有出错。以下是我的代码。

<?php
$db=mysqli_connect('localhost','','','') or die(mysql_error());
                $bookId = $_POST['bookId'];
                $amount = $_GET['amount'];
                $userName = $_SESSION['user'];
                $name = $_GET['name'];
                $sql = "SELECT * FROM booking JOIN product ON (product.name = booking.name) JOIN users ON (users.userName = booking.userName)";
                $resultcount = mysql_query($sql) or die("MySQL error: " . mysql_error());

                if ($resultcount > 0) {
                    mysql_query("UPDATE booking SET amount = '$amount', userName = '" . $_SESSION['user'] . "', name = '$name' WHERE bookId = '$bookId'")
                    or die(mysql_error());
                } else {
                    mysql_query("INSERT INTO booking (bookId, amount, userName, name) VALUES ('$bookId', '$amount', '$userName', '$name')")
                    or die(mysql_error()); 
                }

                    echo "<table border='1' align='center' style='width:800px'>";
                    echo "<tr style='background-color:#d8c7ad;' align='center'><th style='width:100px'>Booking ID</th><th style='width:100px'>User Name</th><th style='width:100px'>Bike Name</th><th style='width:50px'>Amount</th></tr>"; 
                        while($x = mysql_fetch_array($resultcount))
                        {
                            echo "<tr><td>$x[bookId]</td><td>$x[userName]</td><td>$x[name]</td><td>$x[amount]</td></tr>";
                        }
                    echo "</table><br>";

                ?>