t-sql计算年龄

不多说，直接开整。

测试表：

CREATE TABLE [dbo].[staff](
	[id] [varchar](50) NOT NULL,
	[birthdate] [datetime] NULL,
	[age] [int] NULL,
 CONSTRAINT [PK_staff] PRIMARY KEY CLUSTERED 
(
	[id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

　　数据自己加，上存储过程

create proc hr_autochange_age
as
BEGIN
	set nocount on 
	declare age_cur cursor for
		select id,isnull(birthdate,'') from Staff
	open age_cur
	declare @id varchar(255)
	declare @birthday datetime
	fetch age_cur into @id,@birthday
	while @@fetch_status=0
	begin
		IF(@birthday IS NOT NULL AND ISDATE(@birthday) = 1)
			BEGIN
				DECLARE @age INT , @y INT , @m INT , @d INT , @now DATETIME
				SET @now = GETDATE()
				SET @y = DATEPART(YEAR,@now) - DATEPART(YEAR,@birthday)
				SET @m = DATEPART(MONTH,@now) - DATEPART(MONTH,@birthday)
				SET @d = DATEPART(DAY,@now) - DATEPART(DAY,@birthday)
				IF(@m = 0 AND @d = 0)
					BEGIN
						SET @age = @y
					END
				ELSE
					BEGIN
						IF @m > 0 OR (@m = 0 AND @d > 0)
							SET @age = @y
						ELSE
							SET @age = @y - 1
					END
				IF @age < 0 
					SET @age = 0
			END
		ELSE
			BEGIN
				SET @age = NULL
			END
		update Staff set age=@age where id=@id
		fetch age_cur into @id,@birthday 
	end
	close age_cur
	deallocate age_cur
	set nocount off 
END

　　好，完事。