Or is it more like this:

CREATE TABLE #T(Id INT,date1 DATETIME,date2 DATETIME)

INSERT INTO #T

SELECT 1,'2/1/2007','1/31/2010' UNION ALL

SELECT 2,'2/1/2007','2/1/2010' UNION ALL

SELECT 3, '2/1/2007','1/15/2010' UNION ALL

SELECT 4, '2/1/2007','2/2/2010'

SELECT

Id,

date1 AS 'Start',

date2 AS 'End',

DATEDIFF(YEAR, date1, date2) + CASE WHEN DATEADD(yy, -1 * DATEDIFF(YEAR, date1, date2), date2) > date1

THEN 1 ELSE 0

END Years

FROM #T

DROP TABLE #T