PHP ERP Code and Query optimization to improve performance

I am looking for a Freelancer to help me optimize an existing PHP ERP application and its database queries for improved performance. We use PHP and YII Framework. The main project focus is to optimize existing database queries through query optimization techniques. I need a Freelancer who is experienced in working with PHP and database query optimization to help me with this project. The successful applicant must have proven knowledge with designing and developing applications using the PHP language, as well as a strong understanding of database query optimization techniques. The applicant must be able to suggest ways to improve an existing codebase, identify any potential performance issues, and develop solutions to these issues. This project requires a Freelancer with the experience and knowledge to implement the optimized code in an efficient and timely manner.