php - how to sum current Time Stamp with the number of days -

i have column in database contains current_timestamp, want sum time stamp number of days in php , insert result column example if current time stamp (2016-02-06 21:01:27) want sum 3 means 3 days, need help

you can easy. see select. if want update row can direct calculate it

select '2016-02-06 21:01:27' + interval 3 day;   update mytable set newcolumn = mytimestamp + interval 3 day  ....;