日期函數

uses DateUtils

//年初
StartOfTheYear(AValue:TDatetime):TDatetime

//月初
StartOfTheMonth(AValue:TDatetime):TDatetime

//週初
StartOfTheWeek(AValue:TDatetime):TDatetime

//起始時間
StartOfTheDay(AValue:TDatetime):TDatetime

//年底
EndOfTheYear(AValue:TDatetime):TDatetime

//月底
EndOfTheMonth(AValue:TDatetime):TDatetime

//週末
EndOfTheWeek(AValue:TDatetime):TDatetime

//終止時間
EndOfTheDay(AValue:TDatetime):TDatetime