php - 我无法修复的 SQL 错误

Question

我是 php 新手，不知道如何解决以下错误:

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in E:\webareas\hj942\CW\Website\Login\incorrect.php on line 15

我有一个用户表，其角色由普通用户和主席组成。我试图只从角色为 normaluser 的用户表中选择所有内容。我收到上面的错误消息。我的php代码如下:

<?php
include("../includes/db.php");

$username=$_POST['username'];
$password=$_POST['password'];

$username = stripslashes($username);
$password = stripslashes($password);
$username = mysql_real_escape_string($username);
$password = mysql_real_escape_string($password);

$sql="SELECT * FROM Users WHERE username='$username' and password='$password' And role = normaluser";
$result=mysql_query($sql);

$count=mysql_num_rows($result);

if($count==1){
session_register("username");
session_register("password");
header("location:myaccount.php");
}

?>

非常感谢您提供的任何帮助。

Answer 1

试试这个:

$sql="SELECT * FROM Users WHERE username='$username' and password='$password' And role = 'normaluser'";

即:引用角色值。看看是否可行...