create table liu(a varchar2(20),b number(2))
alter table liu rename to jin
rename jin to cai
alter table cai add c varchar2(30)
alter table cai add (d varchar2(30),e number(4))
alter table cai rename column e to f
alter table cai modify d varchar(40)
alter table cai modify f varchar(40)
alter table cai drop column f
本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/zlz_212/archive/2007/11/30/1909196.aspx
