Worked on the apache/calcite repository to enhance the MongoAdapter by implementing complex filter translation for AND and OR operators, enabling support for nested condition queries against MongoDB. Refactored the translation logic within MongoFilter.java to improve maintainability and correctness, laying the foundation for future enhancements in query translation. Expanded automated test coverage in MongoAdapterTest.java to validate the new functionality and ensure regression safety. This work addressed CALCITE-2109, resolving issues with in-condition handling and improving the reliability of query translation across diverse scenarios. Utilized Java and applied expertise in Apache Calcite, database adapters, and query translation throughout the development process.