DATEADD(type, value, date)
- date is the date you want to manipulate
- value is the integere value you want to add (or subtract if you provide a negative number)
- type is one of:
- yy, yyyy: year
- qq, q: quarter
- mm, m: month
- dy, y: day of year
- dd, d: day
- wk, ww: week
- dw, w: weekday
- hh: hour
- mi, n: minute
- ss or s: second
- ms: millisecond
- mcs: microsecond
- ns: nanosecond
