php - 如何检查用户名和密码是否区分大小写？

Question

我制作了一个登录检查脚本，用于检查用户名和密码是否与数据库中设置的帐户相匹配。一切正常，但它不区分大小写，它确实应该是!我该怎么做才能让这个脚本也检查大写/小写？例如:我有一个帐户，用户名:AdMin 密码:My43sGG。如果我在登录字段中输入 admin 和 my43sgg，它也可以工作。

我的脚本:

<?php

// connect to the database
include("config.php");

// username and password sent from form 
$myusername=$_POST['myusername']; 
$mypassword=$_POST['mypassword']; 

// To protect MySQL injection
$myusername = stripslashes($myusername);
$mypassword = stripslashes($mypassword);
$myusername = mysql_real_escape_string($myusername);
$mypassword = mysql_real_escape_string($mypassword);
$sql="SELECT * FROM " .$members. " WHERE username='$myusername' and password='$mypassword'";
$result=mysql_query($sql);

// Mysql_num_row is counting table row
$count=mysql_num_rows($result);

// If result matched $myusername and $mypassword, table row must be 1 row
if($count==1){

// Register $myusername, $mypassword and redirect to file "login_success.php"
session_register("myusername");
session_register("mypassword"); 
header("location:index.php");
}
else {
?>

Answer 1

使用BINARY

WHERE BINARY username = BINARY '$myusername' AND
      BINARY password = BINARY '$mypassword'

• SQLFiddle Demo

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作为旁注，查询易受 SQL Injection 攻击如果变量的值(s) 来自外部。请查看下面的文章，了解如何预防它。通过使用 PreparedStatements，您可以摆脱在值周围使用单引号。

• How to prevent SQL injection in PHP?