仓库管理软件版1楼: 如200508 要返回得到2005/08/31，请各位大虾指教！

2楼: 太简单了:
次月1日-1
给分吧 如销售库存管理软件

3楼: function ReturnLastDay(D: tdatetime): tdatetime;
var
ayear,amonth,aday,AHour,AMinute, ASecond, AMilliSecond:word;
begin
decodedatetime(d,ayear,amonth,aday,AHour,AMinute, ASecond, AMilliSecond);
if amonth =12 then
begin
ayear:=ayear+1;
amonth:=1;
aday:=1
end
else
begin
amonth:=amonth+1;
aday:=1;
end;
result:=strtodatetime(inttostr(ayear)+＇＇-＇＇+inttostr(amonth)+＇＇-＇＇+inttostr(aday))-1;
end;

4楼: uses DateUtils;

function StartOfTheMonth(const AValue: TDateTime): TDateTime;
function EndOfTheMonth(const AValue: TDateTime): TDateTime;
function StartOfAMonth(const AYear, AMonth: Word): TDateTime;
function EndOfAMonth(const AYear, AMonth: Word): TDateTime;

5楼: 先use DateUtils单元；

然后使用EndOfMonth函数就可以。

6楼: 多人接受答案了。