數據庫交互 query

query是個組件，用來生成sql語句,

開啓這個組件，在config/web.php的components中配置

'q'=>'yii\db\Query',

然後再控制器中調用即可

<?php
namespace   app\controllers;
use         app\entry\BasicUser;
use         yii\db\Query;
use         yii\web\Controller;
class DataController extends Controller{

 public function actionQuery(){
     /*
      $res=\yii::$app->q->select('username')
            ->from('test')->where('id=5')
            ->createCommand()->queryAll();
        echo json_encode($res);

        $res=(new Query())->select('username')
            ->distinct(true)->from('test')
            ->createCommand()->queryAll();

        $res=(new Query())->select('username')
           ->from('test')->count('username');



        $res=(new Query())->select('*')
            ->from('test')->limit(10)
            ->offset(0)->orderBy('rest  ')
            ->createCommand()->queryAll();
 */
        $res=(new Query())->select('username')
            ->from('test')->groupBy('username')
            ->createCommand()->queryAll();
        echo json_encode($res);
    }


}