sqlserver中获取月份的天数的方法分享(天数代码)

复制代码代码如下:

 
CREATE FUNCTION [dbo].[udf_DaysInMonth] 

( 

@Date DATETIME 

) 

RETURNS INT 

AS 

BEGIN 

DECLARE @dim AS TABLE (M INT,Dy INT) 

INSERT INTO @dim VALUES 

(1,31),(3,31),(5,31),(7,31),(8,31),(10,31),(12,31), 

(4,30),(6,30),(9,30),(11,30), 

(2, 

CASE WHEN (YEAR(@Date) % 4 = 0 AND YEAR(@Date) % 100 <> 0) OR (YEAR(@Date) % 400 = 0) 

THEN 29 

ELSE 28 END 

) 

DECLARE @RValue INT 

SELECT @RValue = [Dy] FROM @dim WHERE [M] = MONTH(@Date) 

RETURN @RValue 

END 

GO

获取月份天数，以前在博客上也有写过，不过它只是取得二月份的天数。链接如下：http://www.cnblogs.com/insus/articles/2025019.html
现第一眼看见专案中这个函数，总觉它写得不够好的感觉，是否能把它改写得更好些，启发点也是从获取二月份天数的CASE函数想起的。
因此，我尝试改了，如下：

复制代码代码如下:

 
CREATE FUNCTION [dbo].[udf_DaysInMonth] 

( 

@Date DATETIME 

) 

RETURNS INT 

AS 

BEGIN 

RETURN CASE WHEN MONTH(@Date) IN (1,3,5,7,8,10,12) THEN 31 

WHEN MONTH(@Date) IN (4,6,9,11) THEN 30 

ELSE CASE WHEN (YEAR(@Date) % 4 = 0 AND YEAR(@Date) % 100 <> 0) OR (YEAR(@Date) % 400 = 0) 

THEN 29 

ELSE 28 

END 

END 

END

如果你已经有引过Insus.NET那个获取二月份天数的自定义函数，也可以参考下面这个版本：

复制代码代码如下:

 
CREATE FUNCTION [dbo].[udf_DaysInMonth] 

( 

@Date DATETIME 

) 

RETURNS INT 

AS 

BEGIN 

RETURN CASE WHEN MONTH(@Date) IN (1,3,5,7,8,10,12) THEN 31 

WHEN MONTH(@Date) IN (4,6,9,11) THEN 30 

ELSE [dbo].[DaysOfFebruary](YEAR(@Date)) 

END 

END