alter table agent_fee add fixed_fee  FLOAT;
alter table ux5_order_info add courier_no  varchar2(50 char);

comment on column agent_fee.fixed_fee
  is '固定手续费'; 
comment on column UX5_ORDER_INFO.COURIER_NO
  is '快递单号';

原文

创建一个简单视图

CREATE VIEW v_emp AS SELECT * from copy_emp;

CREATE [OR REPLACE] VIEW 视图名 [(alias[,alias]…)] (alias指定视图别名)AS subquery(子查询)[WITH CHECK OPTION[CONSTRAINT constraint]](定义约束)[WITH READ ONLY](只读);