Worked on the apache/calcite repository to enhance SQL interoperability and legacy data handling. Addressed a bug in RelJson timestamp parsing by converting integer representations to long values, ensuring accurate processing of legacy TIMESTAMP and TIMESTAMP_WITH_LOCAL_TIME_ZONE fields. Developed a new feature for dialect-aware numeric literal unparsing, introducing logic in Java to allow SqlDialect to render numeric literals according to each target SQL dialect. Expanded test coverage to validate edge cases in timestamp and numeric literal handling, improving reliability across dialects. Leveraged backend development, compiler techniques, and SQL expertise to strengthen Calcite’s compatibility and reduce maintenance risk for diverse database environments.