title: Sort datatable by hidden column
body: <p>I have <code>datatable</code> with <code>id, firstName, lastName, phone, updated</code> fields. </p>
  
  <p><em><strong>Problem:</em></strong>  I add to <code>datatable</code> only four fields (id, firstName, lastName and phone). <code>Updated</code> field is hidden.</p>
  
  <p><em><strong>Question:</em></strong> how to sort <code>datatable</code> by <code>updated</code> field?</p>
  
  <p><em><strong>My code:</em></strong></p>
  
  <pre><code>   $('#table').dataTable({
          sDom: '&lt;"top"fi&gt;tS',
          sScrollY: ($(window).height() - 250) + "px",
          bPaginate: false,
          bDeferRender: true,
          bAutoWidth: false,
          oLanguage: {
              sInfo: "Total: _TOTAL_ entities",
              sEmptyTable: "No pending entities"
          },
          "aoColumnDefs": [
              { "iDataSort": 4, "aTargets": [ 0 ] }
          ],
          "aoColumns": [
              { "sWidth": "10%" },
              { "sWidth": "40%" },
              { "sWidth": "30%" },
              { "sWidth": "20%" },
              { "sTitle": "updated ", "bVisible":false }
          ],
          fnCreatedRow: function( nRow, aData, iDataIndex ) {
              $(nRow).attr('id', aData[0]);
          }
      });
  
  table.fnAddData([id, firstName, lastName, phone, updated]);
  </code></pre>