<?php
error_reporting(E_ALL);

$con = mysql_connect("localhost","root","alexi") or die('MySQL connect error!');

mysql_select_db("users") or die('MySQL select error!');

if(isset($_POST['Register'])) {
    $username = mysql_real_escape_string($_POST['username']);
    $pass = mysql_real_escape_string($_POST['password']);
    $confirm_password = mysql_real_escape_string($_POST['confirm_password']);

    if(empty($username) || empty($pass) || empty($confirm_password)) {
        echo "You have left empty fields";
    } else {

        $queryuser = mysql_query("SELECT * FROM accounts WHERE username='$username'") or die('Username not found.');

        if(mysql_num_rows($queryuser) != 0) {
            echo "Sorry, ".$username." has already been taken.";
        } else {
            if($pass != $confirm_password)  {
                echo "Passwords do not match";
            } else {
                $password = ($pass);

                $insert_user=mysql_query("INSERT INTO accounts (username, password) VALUES ('$username', '$password')") or die("error in registration " .mysql_error());

                if($insert_user) echo "Registration Successfull";
            }
        }
    }
} else {
    echo "Form unsubmitted";
}
?>