title: Apply query total for variable
body: <p>I have sum query with active record, and assign with total filed.</p>
  
  <p>I select one record is ok, so show as ActiveDataProvider, that total not show.</p>
  
  <p>This my query:</p>
  
  <pre><code>$sumQuery = 'sum(Condition) total';
  </code></pre>
  
  <p>And select sum:</p>
  
  <pre><code> $query-&gt;select(['*', $sumQuery]);
  </code></pre>
  
  <p>So how can i get it's in Data Provinder.</p>