亲测-ubuntu20.04 安装 MySQL5.7

背景介绍

ubuntu 20.04 版本系统自带的 MySQL 版本是 8.0，普通方法很难安装 5.7 版本的。由于 8.0 版本较 5.7 版本做了不少改动，笔者比较习惯使用 5.7 版本。
网上搜做了一圈，跟着各种教程试了很多遍，最后终于找到了成功的方法。过程记录分享出来，供大家参考。

安装过程

笔者的环境：

[email protected]:/home# cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.4 LTS"

1. 若已经安装了 8.0 版本的 MySQL，请先操作删除。

2. 添加 MySQL 源

   sudo vim /etc/apt/sources.list.d/mysql.list

   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

   更新，

   sudo apt update

   执行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 467B942D3A79BD29
   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.

   执行如下命令即可，467B942D3A79BD29根据实际情况替换。

   [email protected]:/home# sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 467B942D3A79BD29

   接着再重新执行更新，

   sudo apt update

3. 安装 MySQL

查看支持的 MySQL 版本，此处我们已经可以看到有 5.7.40-1ubuntu18.04，接近成功了。

[email protected]:/home# sudo apt-cache policy mysql-server
mysql-server:
  Installed: (none)
  Candidate: 8.0.30-0ubuntu0.20.04.2
  Version table:
     8.0.30-0ubuntu0.20.04.2 500
        500 http://mirrors.aliyun.com/ubuntu focal-updates/main amd64 Packages
        500 http://mirrors.aliyun.com/ubuntu focal-security/main amd64 Packages
     8.0.19-0ubuntu5 500
        500 http://mirrors.aliyun.com/ubuntu focal/main amd64 Packages
     5.7.40-1ubuntu18.04 500
        500 http://repo.mysql.com/apt/ubuntu bionic/mysql-5.7 amd64 Packages

安装 MySQL 5.7 版本客户端和服务端，版本信息根据上面的输出自行修改。

sudo apt install mysql-server=5.7.40-1ubuntu18.04
sudo apt install mysql-client=5.7.40-1ubuntu18.04

如无需安装 mysql-client 服务，执行安装 mysql-server 服务，可能会报如下错误。
只需要手动安装 mysql-community-server 即可。sudo apt install mysql-community-server=5.7.40-1ubuntu18.04
The following packages have unmet dependencies:
mysql-server : Depends: mysql-community-server (= 5.7.40-1ubuntu18.04) but it is not going to be installed

4. 验证

   [email protected]:/home# mysql --version
   mysql  Ver 14.14 Distrib 5.7.40, for Linux (x86_64) using  EditLine wrapper

   ok， 完结。踩坑君再次填好一个坑，接着去踩下一个啦。

   参考：

5. Is it possible to install MySQL Server 5.7 on Ubuntu 19.10?
6. Install MySQL 5.7 on Ubuntu 20.04