数据未插入XAMPP数据库

我在注册人员时遇到问题。我试过登录，效果很好。

数据库的脚本

创建表格用户信息(userid INT（4）UNSIGNED NOT NULL AUTO_INCREMENT主键，name VARCHAR（25）NOT NULL，密码VARCHAR（15）不为空，电子邮件VARCHAR（35）不为空)；

PHP代码

$emailErr = $passMismatch = "";
if( isset($_POST['submit']) ){
    if ( $_SERVER["REQUEST_METHOD"] == "POST" ) {
        $name = $_REQUEST['name'];
        $pwd = $_REQUEST['password'];
        $cpwd = $_REQUEST['cpassword'];
        $email = $_REQUEST['email'];
        if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
            $emailErr = "ERROR::Invalid E-Mail Format"; 
        } else $emailErr = "";
        if ( $pwd != $cpwd ) {
            $passMismatch = "ERROR::Passwords Don't Match";
        } else $passMismatch = "";
        $host = "localhost";
        $username = "root";
        $password = "";
        $database = "ontheway";
        $conn = mysqli_connect($host, $username, $password, $database);
        if ( empty($emailErr) && empty($passMismatch) ) {
            $sql = "INSERT INTO userinfo (userid, name, password, email)
                    VALUES (NULL, $name', $pwd', '$email')";

            $result = mysqli_query($conn, $sql);
            if ( !$result ) {
                echo "chala nahi query";
            }
            if ( $result ) {
                session_start();
                $_SESSION['name'] = $name;
                $_SESSION['pass'] = $pass;
                header("location: home.php");    
            }
        }
    }
}

我试着回显问题，但找不到任何问题，$name、$pwd、$cpwd、$email都在回显。甚至错误也完美地显示在表单上。数据库也在连接中。问题出在哪里？请帮忙：）

我总是得到"chala nahi query"，这意味着每次运行这个查询sql都不起作用。

表单代码

名称：

                            <input type="text" name="name" /> <br /> 
                            <p>Password: </p>
                            <input type="password" name="password" /> <br />
                            <?php echo '<h1>'.$passMismatch.'</h1>'; ?>
                            <p>Confirm Password: </p>
                            <input type="password" name="cpassword" /> <br />
                            <p>Email: </p>
                            <input type="email" name="email" /> <br />
                            <?php echo '<h1>'.$emailErr.'</h1>'; ?>
                            <input type="submit" name="submit" />