Function generate_schema_diff 

pub fn generate_schema_diff(
    from_sql: Option<&str>,
    to_sql: &str,
    from_version: Option<&str>,
    to_version: &str,
) -> Result<(String, String), DuckError>

生成SQL架构差异 这个版本专注于生成实际可执行的MySQL差异SQL，而不是简单的文本比较