视图是从一个或者多个表导出的出局，与表非常相似但是视图没有物理记录，不占用物理空间，只是逻辑上存在，保障数据表的安全。

• 创建视图

  create view view_name as select field1,field2 from table;
  create view view_name(field1,field2) as select field1,field2 from table;

• 修改视图

  create or replace view view_name as select field1,field2 from table;
  create or replace view view_name(field1,field2) as select field1,field2 from table;

• 查询视图

  select * from view_name;

• 查看视图

  show create view view_name;
  drop view if exists view_name;