show databases;   #查看所有的数据库

create database myfirst;#创建一个schemas 数据库use myfirst; #进入到这个数据库中show tables; #查看所有表create table myfirst.tableone(id  int not null primary key,name varchar(20) not null,birth date,sex char(1));#创建表describe tableone; #查看表结构alter table tableone add  addr varchar(20)not null;#增加一列alter table tableone drop addr;#删除一列 insert into tableone values('2','flora','1983-08-24','M');#插一条记录select * from tableone; #查看表内容

update tableone set sex='F' where name='flora';#修改

delete from tableone where name='flora';#删除