สอบถาม Codeigniter Pagination อยากรู้ว่าใช้ Where ได้หรือไม่ครับ ของผมใช้แล้วทําให้มันออกผิดพลาดครับ

public function getMusicHiphopPage($num,$offset){
        
        $this->db->limit($num, $offset);
        $this->db->where("music_categories", "Hiphop-Rap");
        $query = $this->db->get('musics');
        
        if($query->num_rows() > 0){
            
            return $query->result();

        }

    }

public function hiphop(){
        
        $this->load->library("pagination");
        $this->load->model("model_music");
        
        $config["base_url"]=base_url()."music/music/hiphop/";
        $config["total_rows"]= $this->db->count_all("musics"); 
        $config["per_page"]=  10;
        $config["full_tag_open"]="<div class='pagination'>";
        $config["full_tag_close"]="</div>";
        $config['uri_segment'] = 4;
        $this->pagination->initialize($config);
       
        $data["result_getmusichiphop"] = $this->model_music->getMusicHiphopPage($config['per_page'],$this->uri->segment(4));
        
        $this->load->view("include/header");
        //$this->load->view("left_menu");
        $this->load->view("music/hiphop-rap",$data);
        $this->load->view("include/footer");
        
    }