This document discusses a novel approach to differential query services in cost-efficient cloud environments, addressing privacy and efficiency issues. It critiques the limitations of existing private keyword retrieval schemes like Ostrovsky's, which incur high computational costs and querying overhead, and introduces efficient information retrieval for ranked queries (EIRQ) to optimize file retrieval by allowing users to specify the rank of matched files. The proposed system significantly reduces bandwidth consumption and enhances user privacy while providing flexible query options.