ubuntu20.04安装Mysql8.0以及mysql密码修改

前言

网上找到的这些关于这类的博客要么就是mysql版本过时了要么就完全没有用，浪费了我好多时间，于是我就把自己成功的经历分享给大家，希望能减少大家走弯路的时间。

Mysql的安装

很简单，一句话

sudo apt install mysql-server

Msql密码的修改

修改密码我们得先进mysql，用管理员权限的话不论你输入什么样的密码都能成功。

sudo mysql -u root -p

进去结果如图所示，表示安装完成

接下来退出登录

quit;

之后对mysql密码的设置初始化

sudo mysql_secure_installation

之后的配置如图设置

#1
VALIDATE PASSWORD PLUGIN can be used to test passwords...
Press y|Y for Yes, any other key for No: N (选择N ,不会进行密码的强校验)

#2
Please set the password for root here...
New password: (输入密码)
Re-enter new password: (重复输入)
(这里他会问你要不要修改密码，第一次选择y)
#3
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...
Remove anonymous users? (Press y|Y for Yes, any other key for No) : N (选择N，不删除匿名用户)

#4
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? (Press y|Y for Yes, any other key for No) : N (选择N，允许root远程连接)

#5
By default, MySQL comes with a database named 'test' that
anyone can access...
Remove test database and access to it? (Press y|Y for Yes, any other key for No) : N (选择N，不删除test数据库)

#6
Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.
Reload privilege tables now? (Press y|Y for Yes, any other key for No) : Y (选择Y，修改权限立即生效)

做完后再登录

sudo mysql -uroot -p

选择mysql database

use mysql;

尝试第一次设置密码，这一次设置有可能会报错Your password does not satisfy the current policy requirements，这是因为你密码的长度不符合长度要求，没报错则无需以下步骤。

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '密码';

若报错则执行以下步骤

SHOW VARIABLES LIKE 'validate_password%';

mysql会输出以下参数

+--------------------------------------+--------+
		| Variable_name                        | Value  |
		+--------------------------------------+--------+
		| validate_password.check_user_name    | ON     |
		| validate_password.dictionary_file    |        |
		| validate_password.length             | 8      |//这个就是你要设置的密码长度
		| validate_password.mixed_case_count   | 1      |
		| validate_password.number_count       | 1      |
		| validate_password.policy             | MEDIUM |
		| validate_password.special_char_count | 1      |
		+--------------------------------------+--------+
		7 rows in set (0.01 sec)

之后就是根据你电脑的参数和这里的参数一个个对照着看，一般来说除了密码长度不一样之外都是一样的，若存在不一直则按如下方法修改。

1 mysql> set global validate_password.policy=0;
	Query OK, 0 rows affected (0.00 sec)

2 mysql> set global validate_password.special_char_count=0;
	Query OK, 0 rows affected (0.00 sec)

3 mysql> set global validate_password.length=6;
	Query OK, 0 rows affected (0.00 sec)

4 mysql> set global validate_password.mixed_case_count=0;
	Query OK, 0 rows affected (0.00 sec)

之后在来看一看参数修改成功没有

mysql> SHOW VARIABLES LIKE 'validate_password%';
	+--------------------------------------+-------+
	| Variable_name                        | Value |
	+--------------------------------------+-------+
	| validate_password.check_user_name    | ON    |
	| validate_password.dictionary_file    |       |
	| validate_password.length             | 6     |
	| validate_password.mixed_case_count   | 0     |
	| validate_password.number_count       | 1     |
	| validate_password.policy             | LOW   |
	| validate_password.special_char_count | 0     |
	+--------------------------------------+-------+
	7 rows in set (0.01 sec)

最后重新输入之前的修改密码的命令。（注意这次密码要和你上面修改的长度一致）

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '密码';

保存设置并退出

flush privileges;

quit;

最后我们来试验一下是否修改成功

mysql -u root -p //这里不要加sudo

输入密码，能进到mysql中不报错就是修改密码成功了。