Outsourced database provides a solution for data owners who want to delegate the task of answering database queries to service provider. Of essential concern in such framework is data privacy. The data owner may want to keep the database hidden from service provider. Simultaneously, potential clients may desire a mean of privacy-preserving computations on outsourced encrypted database. We present a solution of privacy-preserving join query with computational privacy and low overheads. The primary goal of this paper is to provide a set of security notion for such a system as well as a construction which is secure under the newly introduced security notions.