Developed and delivered the Relational Count-If aggregate function for the apache/iotdb repository, enabling conditional counting within relational tables based on boolean expressions. This feature was implemented using Java and SQL, with new accumulator logic designed to support the count_if semantics. Comprehensive integration tests were created to validate both correctness and performance, ensuring the feature’s reliability in production environments. By embedding conditional aggregation directly into the backend, the work enhanced analytics capabilities and reduced the need for post-processing in customer workflows. The approach emphasized maintainability, with clear commit messages and CI-ready tests supporting ongoing development and future auditing requirements.