Oracle update query to sum new value to older

Question

Hello i want update query that adds new value to the older value that is in database. For example 12 value is in amount . If i update this column by putting 13, the result should be 25 (12+13).please help

here is what i tried but it is not working

UPDATE mytable SET amount="12" where name="usman"

Answer 1

UPDATE myTable
SET amount = amount + 13
WHERE name = "usman"