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1.创建数据库：create database [if not exists] databasename;
2.使用数据库：use databasename;
(1).查看表show tables;
(2).创建表：create table `tablename`(`id` int(4) unsigned not null auto_increment primary key comment '编号',`name` varchar(50) not null comment '姓名')engine=InnoDB/MyISAM charset=utf8comment='信息表';
(3).查看表信息：show columns from tablename;
(4)更改表
a.修改表名：alter table tablename rename as new_tablename;
b.增加字段：alter table tablename add id int(4);
c.修改某一列(字段)--单纯更改属性 alter table teacher modify name int(4);
修改某一列--更改列名及属性 alter table teacher change name username varchar(40);
d.删除字段：alter table tablename drop id;
(5).删除表：drop table if exists tablename;
3.删除数据库：drop database if exists databasename;
4.查看数据库：show databases;