13.1 设置更改root密码

设置更改root密码目录概要

/usr/local/mysql/bin/mysql -uroot
更改环境变量PATH，增加mysql绝对路径
mysqladmin -uroot password '123456'
mysql -uroot -p123456
密码重置
vi /etc/my.cnf//增加skip-grant
重启mysql服务 /etc/init.d/mysqld restart
mysql -uroot
use mysql;
update user set password=password('aminglinux') where user='root';

设置更改root密码

root用户是mysql的超级管理员用户，和linux系统的root用户类似，不过和Linux的不一样
默认mysql的 root 用户密码是空的，直接就可以连接上去，不需要输入密码，但是不安全，所以就需要设置一个密码
为了方便使用mysql服务，将mysql目录加入到环境变量里

打开系统，查看mysql是否启动

[root@hanfeng ~]# ps aux |grep mysql
root      1659  0.0  0.1 115392  1712 ?        S    21:29   0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/hanfeng.pid
mysql     2260  0.0 45.3 973548 458428 ?       Sl   21:29   0:02 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=/data/mysql/hanfeng.err --pid-file=/data/mysql/hanfeng.pid
root      2386  0.0  0.0 112676   984 pts/0    R+   22:06   0:00 grep --color=auto mysql
[root@hanfeng ~]#

若是没有启动mysql的话，将mysql启动起来

/etc/init.d/mysqld start

在启动mysql后，使用mysql -uroot命令，但是mysql命令会提示不存在，因为安装的mysql是在/usr/local/mysql/bin/mysql，而这个目录并不在环境变量PATH里面，所以它会报错

[root@hanfeng ~]# mysql -uroot
-bash: mysql: 未找到命令
[root@hanfeng ~]# ls /usr/local/mysql/bin/mysql
/usr/local/mysql/bin/mysql
[root@hanfeng ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
[root@hanfeng ~]#

若想要这个命令直接运行，需要把PATH做一个更改

[root@hanfeng ~]# export PATH=$PATH:/usr/local/mysql/bin/
[root@hanfeng ~]#

这时再来使用mysql -uroot命令就会发现可以使用了

退出mysql输入 quit 即可

[root@hanfeng ~]# mysql -uroot
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 1
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.

mysql> quit
Bye
[root@hanfeng ~]#

若想要变量永久生效，还需要将export PATH=$PATH:/usr/local/mysql/bin/ 放入到 /etc/profile

[root@hanfeng ~]# vim /etc/profile

将内容放到配置文件的最后面，使命令永久生效
export PATH=$PATH:/usr/local/mysql/bin/

保存退出

假设若是没有运行 export PATH=$PATH:/usr/local/mysql/bin/ 命令，那也不能运行mysql，因为变量还没有生效，想要这个变量生效，在配置文件中加入命令后，还需要执行source /etc/profile 命令，重新加载

[root@hanfeng ~]# source /etc/profile
[root@hanfeng ~]#

一般是使用mysql -uroot -p命令

-p，表示指定密码

密码为空的时候，直接回车就可进入到mysql，并可以在其中操作一些mysql的一些行为

[root@hanfeng ~]# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 2
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.

mysql> quit
Bye
[root@hanfeng ~]#

退出mysql，输入 quit 即可
设置mysql密码，命令为mysqladmin -uroot passwd 'hanfeng.1' 在 ' ' 为密码

[root@hanfeng ~]# mysqladmin -uroot password 'hanfeng.1'
Warning: Using a password on the command line interface can be insecure.
[root@hanfeng ~]#

在设置密码的时候，会看到有输出信息，但这不是报错信息，这是告诉你你现在密码在当前命令行显示出来了，这样不太安全
这时在想直接登录mysql，就会提示需要输入密码了

[root@hanfeng ~]# mysql -uroot
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
[root@hanfeng ~]#

在使用-p，并输入密码就可以正常的进入到mysql命令行了

[root@hanfeng ~]# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 7
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.

mysql> quit
Bye
[root@hanfeng ~]#

知道mysql的root密码，去更改密码

若是这时知道mysql密码，去修改mysql密码，看到输出的提示信息不用去理会

格式
- mysqladmin -uroot -p'hanfeng.1' password 'hanfeng'

[root@hanfeng ~]# mysqladmin -uroot -p'hanfeng.1' password 'hanfeng'
Warning: Using a password on the command line interface can be insecure.
[root@hanfeng ~]#

指定新密码去登录，当然也可以不明文指定密码，知道-p回车，输入密码登录也行

[root@hanfeng ~]# mysql -uroot -p 'hanfeng'
Enter password: 
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
[root@hanfeng ~]# mysql -uroot -p'hanfeng'
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 13
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.

mysql> quit
Bye
[root@hanfeng ~]#

在明文指定密码的时候，密码可以加单引号，也可以不加单引号，建议加上单引号，防止密码有特殊符号的存在——>（若是不加单引号，而密码中又有特殊符号，就有可能会不识别）

不知道mysql的root密码，去更改密码

在不知道mysql的root用户密码的时候，先去更改 /etc/my.cnf 下配置文件中加入skip-grant

skip-grant ，表示忽略授权，也就是说操作mysql的时候不需要用户名和密码了，能直接登录

[root@hanfeng ~]# vim /etc/my.cnf

在[mysqld]下面
加入一行
skip-grant

保存退出

在更改配置文件后，重启mysql服务

[root@hanfeng ~]# /etc/init.d/mysqld restart
Shutting down MySQL.. SUCCESS! 
Starting MySQL.. SUCCESS! 
[root@hanfeng ~]#

这时候在输入mysql -uroot ，会发现直接进入mysql，而不需要密码了

[root@hanfeng ~]# mysql -uroot
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 1
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.

mysql>

在登录进mysql后，还需要更改一个表，因为用户名和密码是存在于一个mysql库里面的，使用 use mysql; 切换库，在切换到mysql库里面，然后去更改一个存用户名密码的user表

use mysql; 切换库

mysql> use mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql>

查看user表，输入select * from user; 命令，会看到输出乱七八糟的乱码，里面存放的就是用户名和密码，还有权限和授权等信息

mysql> select * from user;
+-----------+------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+-----------------------+-----------------------+------------------+
| Host      | User | Password                                  | Select_priv | Insert_priv | Update_priv | Delete_priv | Create_priv | Drop_priv | Reload_priv | Shutdown_priv | Process_priv | File_priv | Grant_priv | References_priv | Index_priv | Alter_priv | 

等等等，都是乱码

查看password表，会看到密码都是加密的

mysql> select password from user where user=’root’;
ERROR 1054 (42S22): Unknown column '’root’' in 'where clause'
mysql> select password from user where user='root';
+-------------------------------------------+
| password                                  |
+-------------------------------------------+
| *406D1994F8340A1442C5090388944CCB985BA3DE |
|                                           |
|                                           |
|                                           |
+-------------------------------------------+
4 rows in set (0.00 sec)

mysql>

更改user表，使用update user set password=password('aminglinux') where user='root'; 命令

update user set password=password('aminglinux') where user='root';
- 密码字段函数 //用于加密密码高亮部分：为条件语句

mysql> update user set password=password('aminglinux') where user='root';
Query OK, 4 rows affected (0.00 sec)
Rows matched: 4  Changed: 4  Warnings: 0

mysql>

提示说4行修改完毕，即使有些行是空的
这样密码就更改成功了，输入quit退出数据库即可

mysql> quit
Bye

再去 /etc/my.cnf 配置文件中删除免授权配置，即删除skip-grant——>若是不删除，那么之后所有的用户都不需要输入密码，就可以登录进去，这样安全性太低

[root@hanfeng ~]# vim /etc/my.cnf

在[mysqld]下面删除刚添加的
删除skip-grant

保存退出

重启mysql服务

[root@hanfeng ~]# /etc/init.d/mysqld restart
Shutting down MySQL.. SUCCESS! 
Starting MySQL.. SUCCESS! 
[root@hanfeng ~]#

重启完之后，再用新的密码测试下，会看到新的密码可以登录

[root@hanfeng ~]# mysql -uroot -paminglinux
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 1
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.

mysql> quit
Bye
[root@hanfeng ~]#

这样就是成功更改mysql密码