如下： 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,
如下： 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
