How to add days to a date in PostgreSQL?
I found the following solution

UPDATE table1 set table1.date = (table2.date + (table2.numberOfDays || 'day')::INTERVAL)
FROM tabel2
WHERE table1.id = table2.table1_id


OR

UPDATE table1 set table1.date = table2.date + make_interval(days =&gt; table2.numberOfDays)
FROM tabel2
WHERE table1.id = table2.table1_id