MySQL8.0降級為MySQL5.7

OS：centos 7.6

 

注：更換之前需做好數據庫文件的備份

 

一、卸載MySQL8.0

rpm -qa | grep -i mysql
yum -y remove mysql80-community-release-el7-1.noarch
yum -y remove mysql-community-server-8.0.20-1.el7.x86_64
yum -y remove mysql-community-common-8.0.20-1.el7.x86_64

二、安裝MySQL5.7

  1.下載最新的源碼： 

       官網地址  https://dev.mysql.com/downloads/repo/yum/

 

 

 

wget https://dev.mysql.com/get/mysql80-community-release-el7-1.noarch.rpm

2.安裝源碼

rpm -Uvh mysql80-community-release-el7-1.noarch.rpm

3.查看所有MySQL包

yum repolist all | grep mysql

4.禁用MySQL8.0版本，啟用MySQL5.7版本

yum -y install yum-utils   #安裝yum管理工具，系統默認不安裝
yum-config-manager --disable mysql80-community
yum-config-manager --enable mysql57-community

 

  當enabled=1時，是啟用的；當enabled=0時，是禁用的。也可以進入/etc/yum.repos.d/mysql-community.repo 進行修改設置

5.檢查現在可用版本

 yum repolist enabled | grep mysql

6.等待安裝

yum install mysql-community-server
mysql --version

7.開啟服務

systemctl start mysqld
systemctl enable mysqld

 注：若開啟失敗，需在/var/lib/mysql下新建data目錄，並修改/etc/my.cnf文件對應配置“ datadir=/var/lib/mysql/data”,再次嘗試開啟服務

三、啟動后配置

1.更改MySQL密碼

grep 'temporary password' /var/log/mysqld.log
mysql -u root -p'初始密碼'
ALTER USER 'root'@'localhost' IDENTIFIED BY '123456';

2.允許root用戶遠程連接

use  mysql;
select host, user, authentication_string, plugin from user;
update user set host = "%" where user = "root";
flush privileges;

測試連接並導入已備份數據庫

 

參考文檔：

https://www.cnblogs.com/littlemonsterksn/p/10154662.html

https://blog.csdn.net/jjddrushi/article/details/83827945

https://blog.csdn.net/toooooop8/article/details/103851738( MySQL導入數據庫版本不兼容處理方法)