Is it possible to use UPDATE to change a stored URL?

I have a stored URL something like this: http://www.mysite.com/library/article-name.php

I want to change all URLs in the database with that format to: http://www.mysite.com/library/titles/article-name.php

Is there an easier way to do this than manually changing one entry at a time?

Tried using "UPDATE articles SET url='http://www.mysite.com/library/titles/%' WHERE url='http://www.mysite.com/library/%'". Doesn't work, nor does using LIKE instead of =.