Mysql updating many fields

I want to update many fields randomly in a MySQL table, and I need to update two fields, one using unix timestamp and the other a date. For example, this is what I would have for the unix timestamp:

UPDATE `video` SET addtime= 1264982424 + (1355555555-1264982400)*RAND()

That should update the addtime randomly. However, there is another field in the table that is adddate and this uses mysql date. What can I do so that I write an addtime in Unix that is consistent with the adddate? I'm a bit of开发者_开发百科 a noob in MySQL.

Thanks!

EDITED:
If you need to keep adddate field synchronized with addtime field, you could insert a trigger like this:

CREATE TRIGGER upddate BEFORE UPDATE
FOR EACH ROW BEGIN
    UPDATE video SET NEW.adddate=FROM_UNIXTIME(NEW.addtime);
END;

How about this one?

UPDATE video
SET addtime = 1264982424 + (1355555555-1264982400)*RAND(),
    adddate = FROM_UNIXTIME(addtime)