求两个时间相差，返回年月日应该如何写啊？
做个假设：
时间1：1991年2月15日
时间2: 2013年3月16日

希望得到两个时间的差距值，并以年月日返回。
[解决办法]
这是你要的效果吗？

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DateUtils, ComCtrls, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Memo1: TMemo;
    DateTimePicker1: TDateTimePicker;
    DateTimePicker2: TDateTimePicker;
    DateTimePicker3: TDateTimePicker;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
    function TimeBetween(A, B: TDateTime): string;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
  Memo1.Lines.Add(TimeBetween(DateTimePicker1.Date, DateTimePicker2.Date));
end;

function TForm1.TimeBetween(A, B: TDateTime): string;
var
  Y, M, Day: Integer;
  C, D: TDateTime;
  sA, sB: string;
begin
  if Trunc(A) > Trunc(B) then
  begin
    Result := 'Error';
    exit;
  end;

  if Trunc(A) = Trunc(B) then
  begin
    Result := '0Y0M0D';
    exit;
  end;

  Y := YearsBetween(B, A);

  M := MonthsBetween(B, A);
  M := M - Y * MonthsPerYear;
  Day := DaysBetween(B, A) - Trunc(Y * ApproxDaysPerYear) - Trunc(M * ApproxDaysPerMonth);
  Result := IntToStr(Y) +'Y'+ IntToStr(M) +'M'+ IntToStr(Day) +'D';
end;

end.