Problem with calling MySql store procedure!

Hi every one!
I have a problem with calling MySql store procedure (Line4):

class Category{
    var $db;
    function getCategory(){
        $categoies=$this->db->query('Call get_category();');         //Line 4
        //$categoies=$this->db->query('select * from category');     //Line 5
	return $categoies;
    }
}
	
$cate=new Category();
$cate->db=new mysqli('','root','abc','mydb');
$c=$cate->getCategory();
var_dump($c);
echo '<br />';
	
$c2=$cate->getCategory();
var_dump($c2);

The problem is that:
- If I use Line 4, variable $c will be OK (has record set), but $c2 will be bool(false)
If I use Line 5 is OK.

Please help me because I need to use store procedure!
Thanks!

Tags: PHP, MySQL