MySQL8.0降级安装5.7

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前言

基于OpenHarmony的FA数字管家服务端

默认情况下，Ubuntu20.04安装MySQL的版本为8.0。但8.0更加严格的加密规则，使得一些配置难以实现，故该项目中先进行MySQL 8.0.26 → MySQL 5.7.32

为什么不选择MySQL 5.7的最新版本 5.7.39呢？

我也不知道，反正我一开始降级为5.7.39的时候连mysql的server都跑不起来，所以选择了5.7.32

卸载MySQL 8.0.26

1. 查看MySQL的依赖项

dpkg --list|grep mysql

2. 卸载 mysql-common

sudo apt remove mysql-common

3. 卸载 mysql-server

sudo apt autoremove --purge mysql-server

4. 清除残留数据

dpkg -l|grep ^rc|awk '{print$2}'|sudo xargs dpkg -P

5. 再次查看MySQL的剩余依赖项（一般这时候就卸载干净了）

dpkg --list|grep mysql

6. 继续删除依赖项（如果步骤 5还有剩余依赖，则继续 6）

sudo apt autoremove --purge mysql-apt-config

安装MySQL 5.7.32

MySQL社区版官网：

MySQL_community

1. 找到“DEB Bundle”

2.右击“download”

3.复制链接

终端

下载安装包wget +url

# 5.7.32版本为：
wget https://downloads.mysql.com/archives/get/p/23/file/mysql-server_5.7.32-1ubuntu18.04_amd64.deb-bundle.tar](https://downloads.mysql.com/archives/get/p/23/file/mysql-server_5.7.32-1ubuntu18.04_amd64.deb-bundle.tar

找到下载安装包的路径解压压缩包

tar +压缩包tar

# 5.7.32版本为：
tar -xvf mysql-server_5.7.32-1ubuntu18.04_amd64.deb-bundle.tar

更新依赖源及安装libaio1、libtinfo5依赖

sudo apt-get update
sudo apt-get upgrade
sudo apt-get install libaio1
sudo apt-get install libtinfo5

按下列顺序安装

sudo dpkg -i mysql-common_5.7.32-1ubuntu18.04_amd64.deb
# 下一行代码会进入一个古老的界面，并让你输入密码，这个密码就是mysql的root密码
sudo dpkg-preconfigure mysql-community-server_5.7.32-1ubuntu18.04_amd64.deb 
sudo dpkg -i libmysqlclient20_5.7.32-1ubuntu18.04_amd64.deb
sudo dpkg -i libmysqlclient-dev_5.7.32-1ubuntu18.04_amd64.deb
sudo dpkg -i libmysqld-dev_5.7.32-1ubuntu18.04_amd64.deb
sudo dpkg -i mysql-community-client_5.7.32-1ubuntu18.04_amd64.deb
sudo dpkg -i mysql-client_5.7.32-1ubuntu18.04_amd64.deb
sudo dpkg -i mysql-common_5.7.32-1ubuntu18.04_amd64.deb

继续安装依赖

sudo apt-get -f install
sudo apt-get -f install libmecab2

安装mysql－server

sudo dpkg -i mysql-community-server_5.7.32-1ubuntu18.04_amd64.deb
sudo dpkg -i mysql-server_5.7.32-1ubuntu18.04_amd64.deb

检测安装

mysql -u root -p
# 然后会让输入密码，这个密码就是刚刚设置的密码

显示如下界面表示安装成功

![](https://tva1.sinaimg.cn/large/e6c9d24egy1h0e503ppxnj20vk0amjt0.jpg)

配置MySQL 5.7.32

1. 初始化配置

sudo mysql_secure_installation

2. 配置说明

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

# 2 数据库的root密码，该密码会把上面设置过的root密码覆盖
Please set the password for root here...
New password: # (输入密码)
Re-enter new password: # (重复输入)

# 3  选择N，不删除匿名用户；Y 删除
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) :

# 4  选择N，允许root远程连接；Y 不允许
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) :
# 5 选择N，不删除test数据库；Y 删除
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) : 

# 6  选择Y，修改权限立即生效；N 待会生效
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) :

3. 检查mysql服务状态

systemctl status mysql.service

密码登陆mysql

先登陆mysql mysql

use mysql; #mysql表

# 密码改为自己的root用户密码
update user set authentication_string=PASSWORD("密码") where user='root';

# 更新插件
update user set plugin="mysql_natice_password";

# 刷新权限后退出重新登录即可
flush privileges;
quit;
mysql -u root -p