title: Yii2 Undefined index
body: <p>My controller:</p>
  
  <pre><code>    $params = Yii::$app-&gt;request-&gt;queryParams;
  
      $query4 = (new \yii\db\Query())
      -&gt;select(['monthsubmit', 'modeler'])
      -&gt;from('sku3d')
      -&gt;groupBy(['monthsubmit', 'modeler'])
      -&gt;orderBy(['monthsubmit'=&gt;SORT_DESC]);
  
      $query4-&gt;andFilterWhere(['like', 'monthsubmit', $params['monthsubmit']])
             -&gt;andFilterWhere(['like', 'modeler', $params['modeler']]);
  
      $dataProvider4 = new ActiveDataProvider([
          'query' =&gt; $query4,
      ]);
  </code></pre>
  
  <p>MY view:</p>
  
  <pre><code>&lt;?php echo GridView::widget([
      'dataProvider' =&gt; $dataProvider4,
      'filterModel' =&gt; true,  
      'pjax'=&gt;true,
      'panel' =&gt; [
          'type' =&gt; GridView::TYPE_PRIMARY,
          'heading' =&gt; '&lt;h3 class="panel-title"&gt;&lt;i class="glyphicon glyphicon-user"&gt;&lt;/i&gt;Submitted SKU by Month&lt;/h3&gt;',
      ],
      'columns' =&gt; [
          // 'monthsubmit',
          [
          'attribute'=&gt;'monthsubmit', 
          'filter' =&gt; Html::input('string', 'monthsubmit')
          'width'=&gt;'310px',
          'group'=&gt;true,  // enable grouping
      ],
          [
          'attribute'=&gt;'modeler', 
          'width'=&gt;'180px',
          'filter' =&gt; Html::input('string', 'modeler')
          'group'=&gt;true,  // enable grouping
          ],  
      ]
  ]); 
  ?&gt; 
  </code></pre>
  
  <p>I have created sqlDataProvider in my controller and its working. My problem is when i try to create a filter option since im not using the search model for my gridview, it return error <code>Undefined index: monthsubmit</code>.</p>
  
  <p>Please tell me where I'm wrong.</p>
  
  <p>Thank you.</p>