show tables;
drop table if exists user_new,user_old;
create table user_new(name varchar(25),depart varchar(25),salary int(30));
insert user_new values('张三','主管',1000);
create table users like user_new;
rename table user_new to user_old,users to user_new;
具体使用场景还需要再次推敲和改良