我的SQL查询只返回子对象我也需要父对象

public function getNav($cat,$subcat){
    //gets all sub categories for a specific category
    if(!$this->checkValue($cat)) return false;  //checks data

    $query = false;
    if($cat=='NULL'){
        $sql = "SELECT itemID, title, parent, url, description, image 
                FROM p_cat 
                WHERE deleted = 0
                AND parent is NULL
                ORDER BY position;";
        $query = $this->db->query($sql) or die($this->db->error);
    }else{
        //die($cat);
        $sql = "SET @parent = (SELECT c.itemID FROM p_cat c WHERE url = '".$this->sql($cat)."' AND deleted = 0);

                SELECT c1.itemID, c1.title, c1.parent, c1.url, c1.description, c1.image, (SELECT c2.url FROM p_cat c2 WHERE c2.itemID = c1.parent LIMIT 1) as parentUrl
                FROM p_cat c1
                WHERE c1.deleted = 0
                AND c1.parent = @parent
                ORDER BY c1.position;";
        $query = $this->db->multi_query($sql) or die($this->db->error);
        $this->db->store_result(); $this->db->next_result();
        $query = $this->db->store_result();
    }
    return $query;
}