Date

Get Date

SELECT
	GETDATE() -- returns the current date

Date Add

SELECT
	DATEADD(MINUTE, 20, GETDATE())

-- arg1 - what to add aka: year, month, week, day, hour, minute, second
-- arg2 - how much to add
-- arg3 - what to add to

Date Diff

SELECT
	DATEDIFF(YEAR, GETDATE(), DATEADD(YEAR, 20, GETDATE()))