Código:
procedure TForm1.Button1Click(Sender: TObject);
var
dIni,dFin:Tdate;
begin
dIni:=Date - 365;
dFin:=Date - 300;
Query1.Close;
Query1.Sql.Clear;
Query1.Sql.Add('Select * from Factura ');
Query1.Sql.Add('Where fecha >='+QuotedStr(FormatDateTime('mm/dd/yyyy',dIni)));
Query1.Sql.Add('and fecha <='+ QuotedStr(FormatDateTime('mm/dd/yyyy',dfin)));
Query1.Open;
end;
Un Saludo.