Mysql 5.6修改root密码的方式

1.第一种

[root@centos7 ~]#mysqladmin -uroot -p123456 password aaaaaa
Warning: Using a password on the command line interface can be insecure.
[root@centos7 ~]#mysql -uroot -paaaaaa
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 4
Server version: 5.6.51 MySQL Community Server (GPL)

Copyright (c) 2000, 2021, 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.

(root@localhost) [(none)]> 

2.第二种 (mysql5.6 的安全加固方式)

[root@centos7 ~]#mysql_secure_installation 

NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MySQL
      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!

In order to log into MySQL to secure it, we'll need the current
password for the root user.  If you've just installed MySQL, and
you haven't set the root password yet, the password will be blank,
so you should just press enter here.

Enter current password for root (enter for none): ---这里是如果之前是没有密码的,直接回车,反之输入密码
OK, successfully used password, moving on...

Setting the root password ensures that nobody can log into the MySQL
root user without the proper authorisation.

Set root password? [Y/n] y  ---这里打y 说明确认设置
New password:  ----输入新密码
Re-enter new password: ---确认新密码
Password updated successfully!
Reloading privilege tables..
 ... Success!


By default, a MySQL installation has an anonymous user, allowing anyone
to log into MySQL without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

Remove anonymous users? [Y/n] y   --移除匿名登录的方式
 ... Success!

Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.

Disallow root login remotely? [Y/n] y -----禁止远程登录
 ... Success!

By default, MySQL comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

Remove test database and access to it? [Y/n] y ----移除test数据库
 - Dropping test database...
ERROR 1008 (HY000) at line 1: Can't drop database 'test'; database doesn't exist
 ... Failed!  Not critical, keep moving...
 - Removing privileges on test database...
 ... Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

Reload privilege tables now? [Y/n] y 
 ... Success!


All done!  If you've completed all of the above steps, your MySQL
installation should now be secure.

Thanks for using MySQL!


Cleaning up...

3.第三种 这个好像没什么用，建议用前面两种方式

mysql> update user set Password='MyNewPass4!';
Query OK, 6 rows affected (0.00 sec)
Rows matched: 6  Changed: 6  Warnings: 0

mysql> status
--------------
mysql  Ver 14.14 Distrib 5.6.51, for Linux (x86_64) using  EditLine wrapper

Connection id:		9
Current database:	mysql
Current user:		root@localhost
SSL:			Not in use
Current pager:		stdout
Using outfile:		''
Using delimiter:	;
Server version:		5.6.51 MySQL Community Server (GPL)
Protocol version:	10
Connection:		Localhost via UNIX socket
Server characterset:	latin1
Db     characterset:	latin1
Client characterset:	utf8
Conn.  characterset:	utf8
UNIX socket:		/var/lib/mysql/mysql.sock
Uptime:			12 min 39 sec

Threads: 1  Questions: 67  Slow queries: 0  Opens: 48  Flush tables: 1  Open tables: 41  Queries per second avg: 0.088
--------------