How to select second table in a query?

I am using this to get customer name for auto complete function.

$query = $db->query("SELECT orderr_customer_name FROM orderr WHERE orderr_customer_name LIKE '$queryString%' GROUP by orderr_customer_name LIMIT 10");                if($query) {                    while ($result = $query ->fetch_object()) {                        echo '<li onClick="fill(\''.$result->orderr_customer_name.'\');">'.$result->orderr_customer_name.'</li>';

How can i Select another table? this is the table i want to use

("SELECT customer_name FROM customer WHERE customer_name LIKE '$queryString%' GROUP by customer_name LIMIT 10");

Thanks alot.