Create if not exist else skip

IF NOT EXISTS( SELECT NULL
            FROM INFORMATION_SCHEMA.COLUMNS
            WHERE table_name = 'users')  THEN


ALTER TABLE `users` ADD `klikmissie` int(3) unsigned NOT NULL;
ALTER TABLE `users` ADD `klikdl` int(11) unsigned NOT NULL;
ALTER TABLE `users` ADD `kliktijd` datetime NOT NULL DEFAULT '0000-00-00 00:00:00';
ALTER TABLE `users` ADD `klikken` int(10) unsigned NOT NULL DEFAULT '3600';
ALTER TABLE `users` ADD `kliktijd_2` datetime NOT NULL DEFAULT '0000-00-00 00:00:00';
ALTER TABLE `users` ADD `klikken_2` int(255) NOT NULL default '0';
ALTER TABLE `users` ADD `kliktijd_3` datetime NOT NULL DEFAULT '0000-00-00 00:00:00';
ALTER TABLE `users` ADD `klikken_3` int(255) NOT NULL default '0';
ALTER TABLE `users` ADD `kliktijd_4` datetime NOT NULL DEFAULT '0000-00-00 00:00:00';
ALTER TABLE `users` ADD `klikken_4` int(255) unsigned NOT NULL DEFAULT '0';


END IF;

<?PHP
	include("includes/settings.php");
	
	//error_reporting (E_ALL ^ E_NOTICE); /* Show all errors - no notice */
	ini_set('display_errors', 1);
	ini_set('log_errors', 1);
	ini_set('error_log', dirname(__FILE__) . '/error_log.txt');
	error_reporting (E_ALL ^ E_NOTICE);
  
  	mysql_connect(database_server, database_user, database_pass) or die(mysql_error());
  	mysql_select_db(database_name) or die(mysql_error());
	
	
	
$sql=mysql_query("SELECT * FROM users");


if (!$sql){




mysql_query("ALTER TABLE `users` ADD `klikmissie` int(3) unsigned NOT NULL");
mysql_query("ALTER TABLE `users` ADD `klikdl` int(11) unsigned NOT NULL");
mysql_query("ALTER TABLE `users` ADD `kliktijd` datetime NOT NULL DEFAULT '0000-00-00 00:00:00'");
mysql_query("ALTER TABLE `users` ADD `klikken` int(10) unsigned NOT NULL DEFAULT '3600'");
mysql_query("ALTER TABLE `users` ADD `kliktijd_2` datetime NOT NULL DEFAULT '0000-00-00 00:00:00'");
mysql_query("ALTER TABLE `users` ADD `klikken_2` int(255) NOT NULL default '0'");
mysql_query("ALTER TABLE `users` ADD `kliktijd_3` datetime NOT NULL DEFAULT '0000-00-00 00:00:00'");
mysql_query("ALTER TABLE `users` ADD `klikken_3` int(255) NOT NULL default '0'");
mysql_query("ALTER TABLE `users` ADD `kliktijd_4` datetime NOT NULL DEFAULT '0000-00-00 00:00:00'");
mysql_query("ALTER TABLE `users` ADD `klikken_4` int(255) unsigned NOT NULL DEFAULT '0'");




echo 'groccat created';


}ELSE{


//from here just continue the page as usual!


echo 'groccat already exists!';


}


?>