sql语句（不断总结）

merge语句：

create table person (pid int,page number);

create table newperson (pid int,page number);

e.g

merge into person p1

using newperson p2

on (p1.pid=p2.pid)

when matched then 

   update set p1.page=p2.page

when not matched then

   insert (pid,page) values(p2.pid,p2.page);

级联操作类型：cascade ，set null ，no action

创建ｖｉｅｗ：

create or replace view vew_test(...,...) as select *　from table_name;