مشکل در وارد کردن مقادیر به جدول

[pcmo1]

سلام، ی کد نوشتم قسمت result$ مشکل داره اجرا نمیشه خواهشا کمک کنید خیلی ضروریه


<?php
session_start();
$dbservername = "localhost";
$dbusername = "root";
$dbpassword = "";
$dbname = "library";

$con = mysqli_connect($dbservername, $dbusername, $dbpassword, $dbname) or die ;

$user = $_SESSION['username'];

if (isset($_SESSION['username']) && !empty($_SESSION['username'])){

$table = "CREATE TABLE IF NOT EXISTS ".$user." (
ID INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
user VARCHAR(30) NOT NULL,
uid INT(6) NOT NULL,
book VARCHAR(30) NOT NULL,
bid INT(6) NOT NULL,
writer VARCHAR(30) NOT NULL,
price INT(6) NOT NULL,
mail VARCHAR(30) NOT NULL,
buy_date TIMESTAMP
) ENGINE=InnoDB ";

if ($con->query($table) == FALSE){
echo "Error creating table: " . $con->error;
}}
else{
echo "login error!";
}
$ID = $_POST['ID'];

$bok = "SELECT * FROM books where ID = '$ID' ";
$resultb = $con->query($bok);
$rowb = $resultb->fetch_assoc();

$userr = "SELECT * FROM register where reguser = '$user' ";
$resultu = $con->query($userr);
$rowu = $resultu->fetch_assoc();

$bid = $rowb['ID'];
$book = $rowb['book'];
$price = $rowb['price'];
$writer = $rowb['writer'];
$uid = $rowu['ID'];
$mail = $rowu['regmail'];


if (!$con->set_charset("utf8"))
printf("Error loading character set utf8: %s\n", $mysqli->error);

$sql = "INSERT INTO admin (bid,book,price,writer,uid,mail) VALUES ('$bid','$book','$price','$writer','$uid','$mail')";
$result = $con->query($sql);

if (!$result){
echo "error: ".mysqli_error($sql);
}else{
echo "done!";
}

?>