PHP crypt() password checking

gistfile1.php

<?php

$Password = $_POST['Password'];

$Query = "select `Password` from `Users` where `Username` = '" . mysql_real_escape_string($_POST['Username']) . "'";
$res = mysql_query($Query);
$row = mysql_fetch_assoc($res);
$HashedPassword = $row['Password'];

// Now, what about checking if a password is the right password?
if (crypt($Password, $HashedPassword) == $HashedPassword) {
    echo "Hashed Password matched Password";
}