本篇文章是对如何计算age的sql函数进行了详细的分析介绍，需要的朋友参考下
ALTER FUNCTION [dbo].[get_FullAge]
(
@birthday datetime, @currentDay datetime
)
RETURNS INT
AS
BEGIN
DECLARE @age INT
SET @age = DATEDIFF(YEAR, @birthday, @currentDay)
IF DATEDIFF(DAY, DATEADD(YEAR, @age, @birthday), @currentDay) <= 0
SET @age = @age - 1
IF DATEPART(MONTH, @birthday) = 2 AND DATEPART(DAY, @birthday) = 29 AND DATEPART(MONTH, @currentDay) = 3
AND DATEPART(DAY, @currentDay) = 1 AND
NOT (YEAR(@currentDay) % 4 = 0 AND (YEAR(@currentDay) % 100 !=0 OR YEAR(@currentDay) % 400 = 0))
SET @age = @age - 1
IF @age < 0
SET @age = 0
RETURN @age
END
--Sql根据出生日期计算age（不是很准确）
1. select datediff(year,EMP_BIRTHDAY,getdate()) as '年龄' from EMPLOYEEUnChangeInfo
2. floor((DateDiff(day,u.EMP_BIRTHDAY,getdate()))/365
