While there are:
DATE_ADD - which adds days to a date (though seems like it should be called DAY_ADD, and
MONTH_ADD - which adds months to a date
There is no WEEK_ADD or YEAR_ADD
Both can be done with multiples of DATE_ADD * 7 or MONTH_ADD * 12 but this leads to code that is not particularly clear to read.
Please add
WEEK_ADD and
YEAR_ADD as functions.
EDIT:
MINUTE_ADD AND
SECOND_ADD are also missing