SQL - Conversion Queries

Calculating Age from Date of Birth 

DECLARE @dob  datetime
SET @dob='1992-01-09 00:00:00'

SELECT DATEDIFF(hour,@dob,GETDATE())/8766.0 AS AgeYearsDecimal
    ,CONVERT(int,ROUND(DATEDIFF(hour,@dob,GETDATE())/8766.0,0)) AS AgeYearsIntRound
    ,DATEDIFF(hour,@dob,GETDATE())/8766 AS AgeYearsIntTrunc