DateUtils.YearsBetween();DateUtils.MonthsBetween();DateUtils.WeeksBetween();DateUtils.DaysBetween();DateUtils.HoursBetween();DateUtils.MinutesBetween();DateUtils.SecondsBetween();DateUtils.MilliSecondsBetween();DateUtils.YearSpan();DateUtils.MonthSpan();DateUtils.WeekSpan();DateUtils.DaySpan();DateUtils.HourSpan();DateUtils.MinuteSpan();DateUtils.SecondSpan();DateUtils.MilliSecondSpan();

unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs;type  TForm1 = class(TForm)    procedure FormCreate(Sender: TObject);  end;var  Form1: TForm1;implementation{$R *.dfm}uses DateUtils;procedure TForm1.FormCreate(Sender: TObject);var  t1,t2: TDateTime;  i: Int64;  d: Double;begin  t1 := StrToDateTime('2009-5-20 11:22:33');  t2 := StrToDateTime('2020-9-21 22:33:44');  i := YearsBetween(t1, t2);        //11  i := MonthsBetween(t1, t2);       //136  i := WeeksBetween(t1, t2);        //591  i := DaysBetween(t1, t2);         //4142  i := HoursBetween(t1, t2);        //99419  i := MinutesBetween(t1, t2);      //5965151  i := SecondsBetween(t1, t2);      //357909071  i := MilliSecondsBetween(t1, t2); //357909070999  i := YearsBetween(t2, t1);        //11, 参数无先后  {下面这个系列返回的时间间隔是 Double 类型的, 更精确}  d := YearSpan(t1, t2);        //11.3414540712855  d := MonthSpan(t1, t2);       //136.097448855426  d := WeekSpan(t1, t2);        //591.780871362434  d := DaySpan(t1, t2);         //4142.46609953704  d := HourSpan(t1, t2);        //99419.1863888889  d := MinuteSpan(t1, t2);      //5965151.18333333  d := SecondSpan(t1, t2);      //357909071  d := MilliSecondSpan(t1, t2); //357909071000end;end.