Determine age given date of birth using SQL

The following Microsoft SQL function will help return an integer, determining one's age given date of birth. Hope it helps.

--function to compute age given date of birth
CREATE FUNCTION fnGetAge (@d datetime)
RETURNS INT
AS
BEGIN
    DECLARE @age INT
    SET @age = (
        CASE
            WHEN
                DATEADD(YEAR, DATEDIFF (YEAR, @d, CURRENT_TIMESTAMP), @d) > CURRENT_TIMESTAMP
                THEN DATEDIFF(YEAR, @d, CURRENT_TIMESTAMP) - 1
            ELSE
                DATEDIFF(YEAR, @d, CURRENT_TIMESTAMP)
        END)
    RETURN @age
END
GO

--create table for testing
CREATE TABLE #tem (birthdate DATETIME)
go

--insert some dummy values
INSERT INTO #tem VALUES ('1981-01-09')
INSERT INTO #tem VALUES ('1981-01-10')
INSERT INTO #tem VALUES ('1981-01-11')
INSERT INTO #tem VALUES ('2000-01-01')
INSERT INTO #tem VALUES ('2012-01-01')
GO

--test our function
SELECT birthdate, dbo.fnGetAge(birthdate) FROM #tem
GO