六种不可更新视图

包含以下关键字的sql语句, distinct, group by, having, union, union all

常量视图

create or replace view emp_v
as
select “张三” as name

select中包含子查询

create or replace view emp_v
as
select (select last_name from employees)

join一个不能更新的视图

from一个不能更新的视图

where字句的子查询用了from字句中的表

create or replace view emp_v
as
select e.*
from employees
where employees_id=(
select manager_id
from employees
where manager_id is not null
)