ORACLE1.19-视图view的应用

create view t_myuser as

select

  ooo.*,

  decode(sign((select avg(score)-struts from t_user_score where ke='struts')),1,'是的，低于平均分',-1,'高于平均分','跟平均分持平') low_struts_avg,

  decode(sign((select avg(score)-spring from t_user_score where ke='spring')),1,'是的，低于平均分',-1,'高于平均分','跟平均分持平') low_srping_avg,

  decode(sign((select avg(score)-hibernate from t_user_score where ke='hibernate')),1,'是的，低于平均分',-1,'高于平均分','跟平均分持平') low_hibernate_avg,

  decode(sign((select avg(score)-oracle from t_user_score where ke='oracle')),1,'是的，低于平均分',-1,'高于平均分','跟平均分持平') low_oracle_avg

from (

  select * from (

     (select user_name,ke,score from t_user_score)

  )

  pivot(

      sum(score)             -- 统计值

      for ke in ('struts' as struts,'spring' as spring,'hibernate' as hibernate,'oracle' as oracle)      -- 划分多少列

  )

) ooo

 

select * from t_user_score

 

-- 查询简单多了

select * from t_myuser

-- 条件查询

select * from t_myuser where spring<40

 

--试图view，数据能改吗？

update t_myuser set struts=81 where spring<40

update t_myuser set user_name='小陈' where spring<40

select * from t_user_score

select rowid,user_name from t_myuser