PHP won't update MySQL tables - php

Question

I have a "Windows Apache MySQL PHP" server on my laptop. I get absolutely no error messages, but when I send things to MySQL via PHP script, nothing happens in MySQL (I also sent something via the MySQL command prompt and it looks like it just made a test table and didn't put anything in it like I asked, but I'm not positive I did everything I should have in this case). I've rescripted my whole page a different way and it still doesn't work.
Here is a picture of my form and how the table looks in MySQL:
System:
Windows 7 Home Premium SP1 64 bit--
Apache 2.4.4 32 bit with ssl0.9.8--
PHP 5.4.11 32 bit VC9--
MySQL 5.5.31 64 bit with Navicat Lite
<?php
define('DB_HOST', 'localhost');
define('DB_NAME', 'projectedin');
define('DB_USER','root');
define('DB_PASSWORD','');
$con=mysql_connect(DB_HOST,DB_USER,DB_PASSWORD) or die("Failed to connect to MySQL: " . mysql_error());
$db=mysql_select_db(DB_NAME,$con) or die("Failed to connect to MySQL: " .mysql_error());
function NewUser()
{
$userName = $_POST['username'];
$firstname = $_POST['firstname'];
$lastname = $_POST['lastname'];
$password = $_POST['password'];
$birthday = $_POST['birthday'];
$gender = $_POST['gender'];
$query = "INSERT INTO users (username,firstname,lastname,password,birthday,gender) VALUES ('$username','$firstname','$lastname','$password','$birthday','$gender')";
$data = mysql_query ($query)or die(mysql_error());
if($data)
{
echo "YOUR REGISTRATION IS COMPLETED...";
}
}
function SignUp()
{
if(!empty($_POST['username'])) //checking the 'user' name which is from Sign-Up.html, is it empty or have some text
{
$query = mysql_query("SELECT * FROM users WHERE username = '$_POST[username]' AND password = '$_POST[password]'") or die(mysql_error());
if(!$row = mysql_fetch_array($query) or die(mysql_error()))
{
newuser();
}
else
{
echo "SORRY...YOU ARE ALREADY REGISTERED USER...";
}
}
}
if(isset($_POST['submit']))
{
SignUp();
}
mysqli_close ($con);
?>

Answer 1

There are a number of concerns here (more on that later), but this might be an issue for you:
You try to call your new user function like this:
newuser();
However it is named NewUser. This is case sensitive and will not work. Look at your error logs to see the errrs you are getting here.
Other issues:
You are using deprecated mysql_* functions. If you are learning PHP, learn the right way and use mysqli or PDO.
You are not escaping your input at all, and are therefore very prone to SQL injection attacks.
You are kind of randomly using functions when they don't really bring you any value.
You are kind of going outside of typical PHP coding standard when having your function names start with uppercase letter. This is a bit unusual for PHP, though this would actually work.

Answer 2

You have an error in your Signup query:
$query = mysql_query("SELECT * FROM users WHERE username = '$_POST['username']' AND password = '$_POST['password']'") or die(mysql_error());
I changed $_POST[username] to $_POST['username'] and $_POST[password] to $_POST['password']
Also, you are vulnerable for MySQL injections, you should use mysql_real_scape_string function to clean each $_POST var: $userName = mysql_real_scape_string($_POST['username']);
Finally, you should not use mysql* functions, they are deprecated.