php - 为什么此更新用户密码的代码不起作用？

Question

<?php
include_once 'db.php';
session_start();
if(!$_SESSION['logged_in']) {
  die('You are unauthorized to be here. 1');
}
$old_password = md5($_POST['old_password']);
$new_password = md5($_POST['new_password']);
$sql = "UPDATE users SET pass='?' WHERE user='?' AND pass='?'";
$q = $db->prepare($sql);
$q->bindParam(1, $new_password);
$q->bindParam(2, $_SESSION['username']);
$q->bindParam(3, $old_password);
$q->execute();
header('location: ../?page=account');
?>

这是我的“用户”表方案:

 `users` (`active` int(1) NOT NULL DEFAULT '1',
          `user`   varchar(200) NOT NULL,
          `pass`   varchar(200) NOT NULL,
          `admin`  int(1) NOT NULL,
          `date`   varchar(150) NOT NULL DEFAULT 'error',  
          `Paid`   varchar(200) NOT NULL DEFAULT 'None',
          KEY `user` (`user`) )
 ENGINE=MyISAM DEFAULT CHARSET=latin1;

它根本不更新值...有什么想法吗？

Answer 1

从占位符中删除引号。