title: FireDAC Query connect to DBGrid
body: <p>I have FDQuery and DataSource and DBGrid. Now I write this code in Button</p>
  
  <pre><code>  FDQuery2-&gt;Active = false;
    FDQuery2-&gt;SQL-&gt;Clear();
    FDQuery2-&gt;SQL-&gt;Add(" SELECT C.patient_id, P.patient_name, C.check_id "
                    " FROM Checkup C "
                    " INNER JOIN Patient P ON (C.patient_id=P.patient_id) "
                    " WHERE C.today = " + MaskEdit1-&gt;Text +
                    " ORDER BY C.check_id ");
    FDQuery2-&gt;Active = true;
  </code></pre>
  
  <p>and i connect FDQuery to DataSource and tDataSource to DBGrid, but when I click the Button it doesn't show rows. and i am sure that SQL code is work, because when i write inside the SQL String the rows have been shown.
  any ideas.</p>