Oracle 数据库中下列有返回值的是哪几项？（ABC） A、select 3 from dual where 3 not in (1,2); B、select 1 from dual where 1 in (1,2,null); C、select 1 from dual where 1 in (1,2); D、select 3 from dual where 3 not in (1,2,null);