Over a two-month period, this developer focused on backend stability for the crossoverJie/starrocks repository, addressing critical issues in SQL analysis. They improved the SQL analyzer by fixing logic that previously allowed nested analytic expressions to be misprocessed within window functions, reducing the risk of incorrect analytics results. Using Java and SQL, they implemented regression tests to ensure ongoing reliability and prevent future regressions. Additionally, they refactored error handling for invalid LIKE and REGEXP patterns, leveraging regular expressions and the re2j library to provide clearer error messages. Their work enhanced query validation robustness and improved the overall developer experience.