SQL日期计算问题

[M1234]

如何取得某一年，第N个月份，第M个星期日的日期，例如 2000年5月的第3个星期日

CREATE FUNCTION fn_getDate
(
@p_Year SMALLINT,
@p_Month TINYINT,
@p_N TINYINT
)
RETURNS SMALLDATETIME
AS
BEGIN
...
END

[playwarcraft]

--try:

GO
CREATE FUNCTION fn_getDate
(
@p_Year SMALLINT,
@p_Month TINYINT,
@p_N TINYINT
)
RETURNS SMALLDATETIME
AS
BEGIN
declare @i int,@date SMALLDATETIME
select @date=convert(smalldatetime,rtrim(@p_Year)+'-'+rtrim(@p_Month)+'-1')
set @i=(@p_N-1)*7
while @i<@p_N*7
begin
if datepart(weekday,dateadd(day,@i,@date))=1
begin
break
end
else
set @i=@i+1
end
return dateadd(day,@i,@date)
END
GO

/*
select dbo.fn_getDate(2007,3,2)
---------------------------------
2007-03-11 00:00:00
*/

[playwarcraft]

忘了,最好在之前對輸入的參數加以判斷
筆如@p_N between 1 and 5
@p_Month between 1 and 12 ...

[M1234]

多谢，我试试看