Column.date_add
date_addamountperiod 
Group: DateTime
Documentation
Shifts the date/time by a specified period, returning a new date/time column of the same type.
Arguments
- amount: An integer or integer column specifying by how many periods to shift each date.
- period: The period by which to shift. For- Datecolumns it should be a- Date_Periodand for- Timecolumns it should be a- Time_Period. For- Date_Timecolumns it can be either. It defaults to- Daywhere possible and- Hourfor- Timecolumns.
Remarks
Time Zone handling
Some backends may not preserve the timezone data in a Date_Time
(preserving the represented time instant). This may lead to slight
differences in time calculations between backends, especially around
unusual events like DST.