Join in controller method

declare variable first

protected $db;

then in controller __construct()

$this->db = db_connect();

now your are ready to use.

$this->db->select('tratte_acquistate.*');

Don't work  error : Call to undefined method CodeIgniter\Database\MySQLi\Connection:: select()

---

PHP Code:

public function index()
    {

        $newsMediaModel = new NewsMediaModel();
  
        $result = $newsMediaModel->select()
            ->join('news_post', 'news_post.id = news_media.post_id', 'left')
          
            ->where(['id'=>'2'])

            ->orderBy('id','desc')
            ->paginate(10, 'default',1, 1);

        return $this->respond([
            'data' => $result,
            'pager' => $newsMediaModel->pager->getDetails()
        ], ResponseInterface::HTTP_OK, lang('Shared.api.receive'));


    } 


this is my function :

Code:

public function lista_completa(){

        $tratte_acquistate_model = new Tratte_acquistateModel();

        $result =$tratte_acquistate_model->select('tratte_acquistate.*')
        ->select('tratte_acquistate_extra.*')
        ->select('tratte_acquistate_passeggeri.*')
        ->join('tratte_acquistate_extra', 'tratte_acquistate.id = tratte_acquistate_extra.id_tratte_acquistate')
        ->join('tratte_acquistate_passeggeri', 'tratte_acquistate_passeggeri.id = tratte_acquistate_passeggeri.id_tratte_acquistate')
        ->findAll();

        echo $tratte_acquistate_model->getLastQuery();

        return $result;

                  
}

mysqli_result::fetch_object(): Argument #1 ($class) must be a valid class name, App\Models\EntitiesTratte_acquistate given