IF OBJECT_ID('UDF_Age') IS NOT NULL
DROP FUNCTION UDF_Age
GO

CREATE FUNCTION UDF_Age(
 @Birthday DATETIME
, @Today  DATETIME)
RETURNS INT
AS
BEGIN
 RETURN (DATEDIFF(YY,@Birthday, @Today) - CASE WHEN @Today < DATEADD(YY,DATEDIFF(YY,@Birthday, @Today),@Birthday) THEN 1 ELSE 0 END)

END



/*예제
SELECT dbo.UDF_Age('1977-04-01',GETDATE())
*/