create or replace view ex1 as
select 1 as code ,'' as mc from dual;
create or replace view ex2 as
select 2 as code ,'' as mc from dual;
视图已建立。
视图已建立。
select 1 as code ,'' as mc from dual;
create or replace view ex2 as
select 2 as code ,'' as mc from dual;
视图已建立。
视图已建立。
在pl/sql developer里执行会提示;为非法字符
当然在sql plus逐条输入没有问题
select 1 as code ,null as mc from dual; --改为null