Question: how to calculate years between two dates in sql?
Answer: The query with DATEDIFF: SELECT DATEDIFF(year, '2010-03-13', GETDATE()) AS "Years Difference"; ... 
The query: SELECT *, GETDATE() AS "Current Date", ... 
For Year: year, yy, yyyy.
Month: month, mm, m.
Day of Year: dayofyear, dy, y.
Day: day, dd, d.
Week: week, wk, ww.
Hour: hour, hh.