Worked on the apache/spark repository to enhance SQL window function processing, focusing on correctness, modularity, and performance. Refactored window function validation logic in Scala to enable reuse by the single-pass analyzer, improving code maintainability and reducing runtime validation errors. Updated the WindowResolution component to return WindowExpression objects, streamlining analysis and minimizing unnecessary type casting. Introduced timezone-aware casting in WindowFrame type coercion, ensuring that session timezones are respected and reducing redundant changes after WindowSpecDefinition resolution. Leveraged expertise in Big Data, Spark, and SQL to deliver features that improve reliability and maintainability of windowed query operations within the codebase.