convert to md5 is wrong in php

Question

I have a form in which I am taking username and password from user, and I am converting the password to md5. Then I insert it into database. In user login form, I take the password and convert it to md5. Then I compare both passwords. It matches in some condition but fails if password = p@$$w0rd. What is the issue ? And what is the solution for this issue?

From my form to database password of p@$$w0rd to md5 is b7463760284fd06773ac2a48e29b0acf and from login form it is e22bb24ca616331cb92a48b712034bc3

Code from registration form

$password = trim($_POST['password']);   
$dpassword = md5($password);

And from login form $passwd = md5($password);

$sql = mysql_query("select * from create_dealer where (dealer_email='$user' && password='$passwd')");

Answer 1

The problem is with quotes.

echo md5('p@$$w0rd');// echoes b7463760284fd06773ac2a48e29b0acf
echo md5("p@$$w0rd");// echoes e22bb24ca616331cb92a48b712034bc3

When you use double quotes, $w0rd is considers as an undefined variable and replaced with an empty string.

echo md5("p@$");// echoes e22bb24ca616331cb92a48b712034bc3