How do I write this MySQL Query? (datetime)

Question

Suppose I have a DateTime field called "time_before"

I want to insert a datetime that is 1 hour before the now() time.

INSERT INTO mytable(time_before) VALUES(now()-3600 seconds)...something like this, right?

Answer 1

INSERT INTO mytable(`time_before`) VALUES(NOW() - INTERVAL 1 HOUR)

Answer 2

That's wrong database design. why not to insert just current datetime? All calculations must be done at select time.