How to check username and password case sensitive?

Question

I made a login check script that checks if username and password match an account that is set in the database. All works fine but it isn't case sensitive which it really should be! What can I do to make this script also check for uppercase/lowercase? For example: I have an account with username: AdMin password: My43sGG. If I would enter admin and my43sgg in the login fields it would also work.

my script:

<?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

use BINARY

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

• SQLFiddle Demo

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As a sidenote, the query is vulnerable with SQL Injection if the value(s) of the variables came from the outside. Please take a look at the article below to learn how to prevent from it. By using PreparedStatements you can get rid of using single quotes around values.

• How to prevent SQL injection in PHP?