The transformation language provides built-in date functions so you can perform arithmetic on datetime values as follows:
ADD_TO_DATE.
Add or subtract a specific portion of a date.
DATE_DIFF.
Subtract two dates.
SET_DATE_PART.
Change one part of a date.
You cannot use numeric arithmetic operators (such as + or -) to add or subtract dates.
The transformation language recognizes leap years and accepts dates between Jan. 1, 0001 00:00:00.000000000 A.D. and Dec. 31, 9999 23:59:59.999999999 A.D.
The transformation language uses the transformation Date/Time datatype to specify date values. You can only use the date functions on datetime values.