Change featured image urls in database

Im storing my images on another server and Ive managed to change the urls in the database but I cant seem to change the featured image urls?
I will not be adding any more images so I just want to change the url for all images.
This is the sql I used for normal images

UPDATE wp_posts SET post_content = REPLACE (post_content, 'src="http://www.oldsiteurl.com', 'src="http://newsiteurl.com');

and

UPDATE wp_posts SET  guid = REPLACE (guid, 'http://www.oldsiteurl.com', 'http://newsiteurl.com') WHERE post_type = 'attachment';

All the other images are fine except the featured images.