mySQL question

[Dolby]

In my user table I have an added field called "donator". When the value equals 1 they are a donator (installed the basic donation hack). I now want to put these people in there own user group witch will be user group 12.

What would the mySQL quire be to alter the user group to 12 for all users that have a 1 in the donator field?

I know it would start with something like:

ALTER TABLE user WHERE donator=1 ......or somthing

Thank you in advance for your help.