Replace text with links in doc

Given a table in Mysql with 2 fields key phrases (some are 1 word keywords, others are 2,3 or more words), and urls, I want a function in PHP, that will replace any key phrases in the document with a link of that text, and the url in the table. Just create links for those words. The only trick here is that some words might appear in the key phrases more than one time and they can only be used for one link, example: text: "In the world of cars, the most desired cars are the ones ..." keywords - urls: cars - [login to view URL] desired cars - [login to view URL] In the example, bigger phrases have priority, so the first instance of cars should be replaced with the first link, BUT the second one, because bigger key phrases have priority, should replace desired cars for it's link, and NOT the link for cars. Checked attached document for an html example. This project should not take more than a couple of hours of programming for a regular programmer, so I would like to see bids for $30 or less. thank you