**1.初次启动**
#mysql
mysql> update mysql.user set    authentication_string='newpass',plugin='mysql_native_password ' where user='root';
 
mysql> flush privileges;
 
mysql> exit;

$ mysql  -u  root  -p                          //本地登陆
$ mysql -u love -p -h ip                 //远程登陆

**2.用户操作**
mysql> use mysql;
mysql> create user 'love'@'localhost' identified by 'love';        //创建用户

mysql> flush privileges;

mysql> grant all  on mysql.user to love@localhost;                      //授权

mysql> show grants for love@localhost;                                        //查看授权

mysql> revoke all on mysql.user from love@localhost;             //取消授权
 
mysql> update user set authentication_string='newpass' where user='love';  //修改密码

 mysql> delete from user where user='love';                                //删除用户

 mysql> drop user love@localhost;                                                //删除用户

**3.查询**
 mysql>  show databases;                              //查询数据库（根据用户权限）
 
 mysql>  show tables;                                     //查询当前数据库有哪些表
 
 mysql>  show columns from user;             //查询user表所有列的列名和属性
 
  mysql> select count(*) from user;             //查询有多少条记录
 
4.DDL数据定义
mysql> create database abc;                            //创建数据库abc

mysql> create table user_info(                        //创建user_info表
         >> id int primary key,                                 //id列int类型, 主键
         >> name varchar(255) unique，             // name列字符串类型，唯一约束
         >> family text not null);                            //family列text类型，非空
 
mysql> alter table user_info rename to info;         //改表名
mysql> alter table info add phone int;                    //增加列
mysql> alter table info change column phone pho int;       //改列名
mysql> alter table info drop column phone;         //删除列
            

5.DML数据操作
mysql> insert into t1
mysql> delete from t1
mysql> update t1 set 
mysql> select id from t1