Worked on improving SQL DDL rendering correctness in the apache/doris repository, focusing on backend development and database reliability. Addressed a bug in the ColumnDef.java file by refactoring the toSql method to handle default value scenarios across various data types, including quoted strings and complex types such as BITMAP and HLL. Enhanced maintainability and readability of the code while ensuring accurate representation of default values in SQL column definitions. Added comprehensive tests to cover multiple data types and edge cases, providing regression protection. Utilized Java and SQL to support more reliable schema migrations and consistent downstream tooling for client workflows.