search query analyzer

Hi I am looking for some good ideas to combine some fields with query operators (multiple words, or/and, >/„/¾<, range of numerical values...). Let's say I have 2 fields (numerical & text) to combine where the serach criteria can be as complicated as this : - year : >1950, 1960-1965, not1980-2000, >2002 - subject : (boy and bicycle) or (man and tractor) Is there a bullet proof function that can filter such field values and return a valid sql query? What are the basic rules and operators to use? Thanks for pointing out relevant link or good advice. -- Kind regards, Paul. Gondwana Info@gondwanastudio.com http://www.gondwanastudio.com