1 IF EXISTS(SELECT 1 FROM sysobjects WHERE [name] = 'GetAge')
2 DROP FUNCTION dbo.GetAge
3 go
4 CREATE FUNCTION dbo.GetAge
5 (
6 @birthday DATETIME
7 )
8 RETURNS INT
9 AS
10 BEGIN
11 IF(@birthday IS NOT NULL AND ISDATE(@birthday) = 1)
12 BEGIN
13 DECLARE @age INT , @y INT , @m INT , @d INT , @now DATETIME
14 SET @now = GETDATE()
15 SET @y = DATEPART(YEAR,@now) - DATEPART(YEAR,@birthday)
16 SET @m = DATEPART(MONTH,@now) - DATEPART(MONTH,@birthday)
17 SET @d = DATEPART(DAY,@now) - DATEPART(DAY,@birthday)
18 IF(@m = 0 AND @d = 0)
19 BEGIN
20 SET @age = @y
21 END
22 ELSE
23 BEGIN
24 IF @m > 0 OR (@m = 0 AND @d > 0)
25 SET @age = @y
26 ELSE
27 SET @age = @y - 1
28 END
29 IF @age < 0 SET @age = 0
30 END
31 ELSE
32 BEGIN
33 SET @age = NULL
34 END
35 RETURN @age
36 END