Controller Highchart Yii2

public function actionIndex(){
        $_xseries = $db->createCommand("SELECT DISTINCT MONTHNAME(STR_TO_DATE(MONTH(omset.omset_date), '%m')) as xseries FROM omset ORDER BY MONTH(omset.omset_date) ASC")->queryAll();
        $_nseries = $db->createCommand("SELECT DISTINCT omset.omset_site_code FROM omset")->queryAll();
        $_xseries_data = array();
        $data_series =array();
        $_data = array ();
        $_data_series = array ();

        foreach ($_xseries as $xs)
        {
            $_xseries_data[] = $xs["xseries"];
        }

        foreach ($_nseries as $ns)
        {
            array_push($data_series,array("name"=>$ns["omset_site_code"],));
        }

        foreach ($data_series as $ds)
        {
            $months = $db->createCommand("SELECT DISTINCT omset.omset_site_code, SUM(omset.omset_nominal) as omset_nominal, MONTHNAME(STR_TO_DATE(MONTH(omset.omset_date), '%m')) as `month` FROM omset WHERE omset.omset_site_code = '".$ds["name"]."' GROUP BY MONTH(omset.omset_date), omset.omset_site_code")->queryAll();

            foreach ($months as $m)
            {
                $_data_series[] = (int)$m["omset_nominal"];
            }
            array_push($_data,array(
                'name'=>$ds["name"],
                'data'=>$_data_series,
            ));
            unset($_data_series);
        }
        return $this->render('index',[
                'chart_x_axis' => $_xseries_data,
                'chart_x_series' => $_data,
            ]);
}