Некорректный поиск по дате

if (DateEdit1.Text<>'  .  .    ') and (DateEdit2.text<>'  .  .    ') then
begin
PorojnieQ.SQL.Clear;
PorojnieQ.SQL.Add('SELECT * FROM wagon_data WHERE (wagon_data.date_doroga_in >=:dt1) and (wagon_data.date_doroga_in <= :dt2) and (wagon_data.[otprav_name]="ÏÎÐÎÆÍÈÉ")');
PorojnieQ.Parameters.ParamByName('dt1').Value := DateEdit1.date;
PorojnieQ.Parameters.ParamByName('dt2').Value := DateEdit2.date;
 
  s := 3; //íîìåð ñòðîêè
  Excel := CreateOleObject('Excel.Application');
  try
    Workbook := Excel.Workbooks.Add('C:\Poroj.xlsm');
    Worksheet := Excel.WorkBooks[1].WorkSheets['Export'];
    with PorojnieQ do
    try
      Open;
      PorojnieQ.First;
  for i:=0 to PorojnieQ.RecordCount-1 do
  begin
  for j:=0 to PorojnieQ.FieldCount-1 do
  excel.WorkSheets[1].Cells[s,j+1]:=PorojnieQ.Fields[j].AsString;
  inc(s);
  PorojnieQ.Next;
  end;
    finally
      Close;
    end;
  finally
    Excel.Visible := True;
    Excel := Unassigned;
  end;
  Close;
end
else MessageDlg('Ââåäèòå ïðàâèëüíûé äèàïîçîí äàò',mtWarning,[mbOK],0);

DateToStr(DateEdit1.Date) + ' 23:59:59'

QMain.Active:=False;
QMain.SQL.Strings[2]:='WHERE (((Tbl.Date)>:Date))';
QMain.Parameters.ParamByName('date').Value:=StrToDateTime('07.04.2012 12:00:00');
QMain.Active:=true;