select  StaDateTime,
        EndDateTime,
        DateTime,
        Total
from    table1
union all
select  'Total' as StaDateTime,
        null as EndDateTime,
        sum(DateTime) as DateTime,
        sum(Total) as Total,
from    table1

 
procedure TForm1.Button1Click(Sender: TObject);
var
  Total_DateTime,Total_Total:integer;
begin
  Total_DateTime:=0;
  Total_Total:=0;
  with query1 do
    begin
      close;
      sql.Clear;
      sql.Add('select * from table1');
      open; 
      first;
      while not eof do
        begin
          Total_DateTime:=Total_DateTime Fieldbyname('DateTime').AsInteger; 
          Total_Total:=Total_Total Fieldbyname('Total').AsInteger; 
          next;
        end;
      append;
      Fieldbyname('StaDateTime').Asstring:='Total';
      Fieldbyname('EndDateTime').Asstring:=' ';
      Fieldbyname('DateTime').AsInteger:=Total_DateTime;
      Fieldbyname('Total').AsInteger:=Total_Total;
      post;
    end;
end;