SQL query: find and replace by user
 

I would like to replace all the instances of a string of text in the body of a post* but only where a specific user posted it.

In my case* I have a user spamming the forum with a URL that consists of pretty common words. (Something like 'mycoolsite.com' or something). To get around some filters* he has used variations* such as 'my cool site.com'* so I would like to mass-replace all instances of 'my cool site' with something like 'removed'* but only in his posts* not the posts of other people.

Does anybody know the SQL query for this? I have this* for a simple find and replace:

Code:
UPDATE post SET pagetext = REPLACE(pagetext* 'annoyinguser'* 'gonenow');