class="toc">文章目录
root@iZ7xvhuhaslv4h5dm1d1svZ:~# cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.6 LTS"
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">查看是否有正在运行的 MySQL 服务进程 或者 maridb 服务进程
root@iZ7xvhuhaslv4h5dm1d1svZ:~# ps axj | grep mysql # 有正在运行的
1 7069 7068 7068 ? -1 Sl 108 0:01 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
941 7223 7222 941 pts/0 7222 S+ 0 0:00 grep --color=auto mysql
root@iZ7xvhuhaslv4h5dm1d1svZ:~# ps axj | grep maridb # 没有正在运行的
941 7225 7224 941 pts/0 7224 S+ 0 0:00 grep --color=auto maridb
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">如果有就关闭正在运行的MySQL服务进程，并继续下面的卸载工作，没有则跳到第二步的安装过程
sudo systemctl stop mysql
sudo systemctl stop maridb
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">然后开始卸载 MySQL
卸载第一步：使用 apt-get 移除 MySQL 软件包
sudo apt-get remove --purge mysql-server mysql-client mysql-common
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">在跳出来的页面中选择 Yes
卸载第二步：删除残留的配置文件
sudo rm -rf /etc/mysql # MySQL 的配置文件所在目录
sudo rm -rf /var/lib/mysql # MySQL 的数据存储目录
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">打开 /etc/apt/sources.list.d/mysql.list
sudo vim /etc/apt/sources.list.d/mysql.list
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">添加如下内容
deb http://repo.mysql.com/apt/ubuntu/ bionic mysql-apt-config
deb http://repo.mysql.com/apt/ubuntu/ bionic mysql-5.7
deb http://repo.mysql.com/apt/ubuntu/ bionic mysql-tools
deb-src http://repo.mysql.com/apt/ubuntu/ bionic mysql-5.7
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">更新本地的 apt 包索引
sudo apt update
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">更新过程中可能会出现如下错误
W: GPG error: http://repo.mysql.com/apt/ubuntu bionic InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B7B3B788A8D3785C
E: The repository 'http://repo.mysql.com/apt/ubuntu bionic InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">这是由于缺少MySQL APT存储库的公钥导致的，运行以下命令来添加公钥
wget https://repo.mysql.com/RPM-GPG-KEY-mysql-2023
sudo apt-key add RPM-GPG-KEY-mysql-2023
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">再次更新 apt 包索引
sudo apt update
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">查看系统支持的 MySQL 版本，此处可以看到已经有 5.7.42-1ubuntu18.04 了
root@iZ7xvhuhaslv4h5dm1d1svZ:~# sudo apt-cache policy mysql-server
mysql-server:
Installed: (none)
Candidate: 8.0.37-0ubuntu0.20.04.3
Version table:
8.0.37-0ubuntu0.20.04.3 500
500 http://mirrors.cloud.aliyuncs.com/ubuntu focal-updates/main amd64 Packages
500 http://mirrors.cloud.aliyuncs.com/ubuntu focal-updates/main i386 Packages
500 http://mirrors.cloud.aliyuncs.com/ubuntu focal-security/main amd64 Packages
500 http://mirrors.cloud.aliyuncs.com/ubuntu focal-security/main i386 Packages
8.0.19-0ubuntu5 500
500 http://mirrors.cloud.aliyuncs.com/ubuntu focal/main amd64 Packages
500 http://mirrors.cloud.aliyuncs.com/ubuntu focal/main i386 Packages
5.7.42-1ubuntu18.04 500
500 http://repo.mysql.com/apt/ubuntu bionic/mysql-5.7 amd64 Packages
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">先后安装 MySQL 5.7 版本客户端和服务端，版本信息根据自己的输出自行修改。
sudo apt install -y mysql-client=5.7.42-1ubuntu18.04
sudo apt install -y mysql-server=5.7.42-1ubuntu18.04
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">server 端安装过程中会自动出现如下界面，可凭喜好是否设定root用户密码
安装好了之后使用 which 查看说明安装完成
root@iZ7xvhuhaslv4h5dm1d1svZ:~# which mysqld # 查看服务端
/usr/sbin/mysqld
root@iZ7xvhuhaslv4h5dm1d1svZ:~# which mysql # 查看客户端
/usr/bin/mysql
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">/etc/mysql 是 MySQL 相关配置文件所在目录，其中 conf.d 是客户端配置文件所在目录，mysql.conf.d 是服务端配置文件所在目录，MySQL 5.7 并没有显式将配置文件分开，而是 Ubuntu 20.04 的安装过程中，将 MySQL 的配置文件分为服务端和客户端部分。
root@iZ7xvhuhaslv4h5dm1d1svZ:~# cd /etc/mysql/
root@iZ7xvhuhaslv4h5dm1d1svZ:/etc/mysql# ll mysql.conf.d/ conf.d/
conf.d/:
total 16
drwxr-xr-x 2 root root 4096 May 8 11:14 ./
drwxr-xr-x 4 root root 4096 Jun 16 20:46 ../
-rw-r--r-- 1 root root 8 Aug 3 2016 mysql.cnf
-rw-r--r-- 1 root root 55 Aug 3 2016 mysqldump.cnf
mysql.conf.d/:
total 12
drwxr-xr-x 2 root root 4096 Jun 16 20:46 ./
drwxr-xr-x 4 root root 4096 Jun 16 20:46 ../
-rw-r--r-- 1 root root 1587 Mar 16 2023 mysqld.cnf
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">首先是客户端
sudo vim /etc/mysql/conf.d/mysql.cnf
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">添加如下内容，主要是为了解决汉字兼容问题
# 设置mysql客户端默认字符集
default-character-set=utf8
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">然后是服务端
sudo vim /etc/mysql/mysql.conf.d/mysqld.cnf
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">添加如下内容
#设置3306端口
port=3306
# 服务端使用的字符集默认为8比特编码的latin1字符集
character-set-server=utf8
# 创建新表时将使用的默认存储引擎
default-storage-engine=innodb
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">重启 MySQL 服务端
systemctl restart mysql.service
class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}">以上就是所有的安装过程
评论记录：
回复评论：