[SQL Server] 날짜 연산

DATEDIFF()

http://technet.microsoft.com/ko-kr/library/ms189794.aspx

DATEDIFF ( datepart , startdate , enddate ) :int

DATEADD()

http://technet.microsoft.com/ko-kr/library/ms186819.aspx

DATEADD (datepart , number , date ) :date

datepart	약어
year	yy, yyyy
quarter	qq, q
month	mm, m
dayofyear	dy, y
day	dd, d
week	wk, ww
hour	hh
minute	mi, n
second	ss, s
millisecond	ms
microsecond	mcs
nanosecond	ns