Need help writing a MySQL query

[TeddyKGB]

SO I am working with another board to merge our two boards together and after I used Impex it appears a handful of users get imported but their userid is set to 0. This means when you look at a post made by that user the username is not clickable. I want to update those specific users to another pre-existing username and userid but I don't know how to write update queries.

Here is the query I get from MySQL when I do a search on the "post" table.

SELECT *
FROM `post`
WHERE `username` LIKE CONVERT( _utf8 'J'
USING latin1 )
COLLATE latin1_swedish_ci
AND `userid` =0
LIMIT 0 , 30

How do I alter that to update the username to 'TeddyKGB' and userid to 460?