参考此帖：http://topic.csdn.net/u/20110416/13/1878ce94-6154-43a3-9b23-f5ff8c06f164.html 如果您无法打开此链接，也可以下载此论题图http://download.cnblogs.com/insus/Miscellaneous/Insus_Birthdate_Cal_Age.rar。
根据出生日期计算出在某个事件日期当时的年龄。因为Insus.NET把它写成一个自定义函数UDF_Age:
View Code
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
IF OBJECT_ID('[dbo].[udf_Age]') IS NOT NULL
DROP FUNCTION [dbo].[udf_Age]
GO
CREATE FUNCTION [dbo].[udf_Age](
@BirthDate DATETIME,
@EventDate DATETIME
)
RETURNS INT
AS
BEGIN
--没有超过一岁的，均为0岁
RETURN DATEDIFF(YEAR, @BirthDate,@EventDate) - CASE WHEN 100 * MONTH(@EventDate) + DAY(@EventDate) < 100 * MONTH(@BirthDate) + DAY(@BirthDate)
THEN 1 ELSE 0 END
END
GO
SET QUOTED_IDENTIFIER ON
GO
IF OBJECT_ID('[dbo].[udf_Age]') IS NOT NULL
DROP FUNCTION [dbo].[udf_Age]
GO
CREATE FUNCTION [dbo].[udf_Age](
@BirthDate DATETIME,
@EventDate DATETIME
)
RETURNS INT
AS
BEGIN
--没有超过一岁的，均为0岁
RETURN DATEDIFF(YEAR, @BirthDate,@EventDate) - CASE WHEN 100 * MONTH(@EventDate) + DAY(@EventDate) < 100 * MONTH(@BirthDate) + DAY(@BirthDate)
THEN 1 ELSE 0 END
END
演示：
SELECT [dbo].[udf_Age]('1988-08-06','2011-04-18')
结果：
