<?php
$con = mysql_connect("localhost","root","password") or die(mysql_error());
mysql_select_db("learning",$con) or die(mysql_error());
echo "Connection established, DB selected <br />";
$user = mysql_real_escape_string($_GET['user']);
$pass = mysql_real_escape_string($_GET['pass']);
$email = $_GET['email'];
/*Check to see if user is registered*/
if(isset($user,$pass)){
$array = mysql_query("select * from knowledge");
while($ar = mysql_fetch_array($array)){
$check = $ar['user'];
if($check == $user){
echo "User already exists!";
exit(0);
  }
}
$sql = "insert into knowledge(user,passw) values('$user',md5('$pass'))";
mysql_query($sql) or die(mysql_error());
}
?>