Boolean SQL query builder

I'm in the process of coding a db search engine, and am spending excessive amounts of time putting together a SQL 'query builder' function which will turn this: mon* NOT monkey [AND/OR queries also] ...into this: SELECT * FROM table WHERE field LIKE 'monk%' AND NOT field = 'monkey' Basically, my thinking was that this will have been done many times before, and be available readily on Hotscripts or the PHP Resource Index.. but all I've managed to turn up so far is phpSQLbool (http://sourceforge.net/projects/phpsqlbool/) which is, by the author's admission, not very complete at the moment. So... has anyone written a similar function that will do the above? :) Many thanks, Chris