calculation

I have designed a movie rental database in oracle which consits of 5 tables store, movie, rental, transaction and customer. i want to calculate the total cost in the transaction table by getting the movie rent price from the movie table n the total days from the rental table. i also want to get the difference of the daterented and datereturned to get total days in the rent table. can anyone help?? ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Installation package that will install the software (in ready-to-run condition) on the platform(s) specified in this bid request. 3) Exclusive and complete copyrights to all work purchased. (No GPL, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site). ## Platform oracle 8i database