为什么我的PHP注册不起作用？

我对我的PHP登录脚本有一个问题。我对PHP和MySQL非常陌生，所以在查看我的代码时请记住这一点

<?php

include('connectdb.php')

//define
$myusername=$_POST['myusername'];
$mypassword=$_POST['mypassword'];
$passwordconfirm=$_POST['passwordconfirm'];
$email=$_POST['email'];
$firstname=$_POST['firstname'];

//prevents from MySQL Injection
$myusername = stripslashes($myusername);
$mypassword = stripslashes($mypassword);
$passwordconfirm = stripslashes($passwordconfirm);
$email = stripslashes($email);
$firstname = stripslashes($firstname);
$myusername = mysql_real_escape_string($myusername);
$mypassword = mysql_real_escape_string($mypassword);
$passwordconfirm = mysql_real_escape_string($passwordconfirm);
$email = mysql_real_escape_string($email);
$firstname = mysql_real_escape_string($firstname);

//Inserting In to Table
$sql = "INSERT INTO login3 (username, password, confirmpass, email, firstname)
VALUES ($myusername, $mypassword, $passwordconfirm, $email, $firstname)";

?>

---

这不应该将所有值插入表login3吗？

插入时，您没有对字符串使用引号。你也应该使用反勾号。您还应该使用mysqli_*而不是mysql_*函数，因为它们已被弃用。此外，没有理由像@AndyIbanez所说的那样存储已确认的密码，从而改变您的表结构。您甚至还没有查询sql语句。试试这个：-

$sql = "INSERT INTO `login3` (`username`, `password`, `email`,    
`firstname`)
VALUES ('$myusername', '$mypassword', '$email', '$firstname')"; 

$conn = new mysqli($host, $user, $password, $database);
if(!$conn->query($sql)){
    echo "ERROR : " . mysqli_error($conn);//this will display error while insering into the table
}

使用此查询

$sql = "INSERT INTO login3 ('username', 'password', 'confirmpass', 'email', 'firstname')
VALUES ('".$myusername."', '".$mypassword."', '".$passwordconfirm."', '".$email."', '".$firstname."')";

---

在这么少的代码行中有这么多的不推荐，你不应该再使用mysql\uuAPI了。改用PDO。另外，我不知道你为什么要插入密码和重复密码。最后，你不是。