php mysql code

<?php


if(!empty($_POST['username']) &&!empty($_POST['email']) &&!empty($_POST['password'])) {
	$username=$_POST['username'];
	$email=$_POST['email'];
	$password=$_POST['password'];


	$con=mysql_connect('localhost','root','') or die(mysql_error());
	mysql_select_db('registration', $con) or die("cannot select DB");

	$query=mysql_query("SELECT * FROM reg1 WHERE username='".$username."'");
	$numrows=mysql_num_rows($query);
	if($numrows==0)
	{
	$sql="INSERT INTO reg1 (username,email,password) VALUES('$username','$email','$password')";

	$result=mysql_query($sql);


	if($result){
	echo " Your Account Has Been Successfully Created!.";
	} else {
	echo "Failure!";
	}

	} else {
	echo "The username you have entered already exists!.";
	}

} else {
	echo "All fields are required!";
}


?>