cxgrid footer summary value by a column

var

  AIndex: integer;

  AValue: variant;

begin

 with cxGrid1DBTableView1.DataController.Summary do

    begin

      AIndex :=  DefaultGroupSummaryItems.IndexOfItemLink(cxGrid1DBTableView1DBColumn2);

      AValue :=  DefaultGroupSummaryValues[AIndex]

    end;

  pplabel6.Caption := VarToStr(AValue);

var

  AIndex, AGroupIndex: integer;

  AValue: variant;

begin

  with <AcxGridDBTableView>.DataController do

  begin

    AGroupIndex := Groups.DataGroupIndexByRowIndex[<ARowIndex>];

    AIndex := Summary.DefaultGroupSummaryItems.IndexOfItemLink(<AColumn>);

    AValue := Summary.GroupSummaryValues[AGroupIndex, AIndex];

  end;

  Caption := VarToStr(AValue);

end;