|  | 
 
 | 因為CentOS7.6改成MySQL 5.7版後,居然mysql資料庫下的user表下居然沒有password欄位,所以怎麼樣都無法設定root的密碼,指令 mysqladmin -u root password "newpassword" 居然無法使用,找了古歌大神之後,才發現必須降回MySQL5.6才行 
 改repo
 
 複製代碼 vi /etc/yum.repos.d/mysql-community.repo
[mysql56-community]
 改
 enable=1
 
 [mysql57-community-dmr]
 改
 enable=0
 
 存檔離開
 
   
 伺服器端端
 一,安裝
 
 複製代碼//1.先安装带有可用的mysql5系列社区版资源的rpm包
[root@iZ28gvqe4biZ ~]# rpm -Uvh http://dev.mysql.com/get/mysql-community-release-el7-5.noarch.rpm
获取http://dev.mysql.com/get/mysql-community-release-el7-5.noarch.rpm
准备中...                          ################################# [100%]
正在升级/安装...
   1:mysql-community-release-el7-5    ################################# [100%]
複製代碼//2.查看当前可用的mysql安装资源
[root@iZ28gvqe4biZ ~]# yum repolist enabled | grep "mysql.*-community.*"
mysql-connectors-community/x86_64 MySQL Connectors Community                  17
mysql-tools-community/x86_64      MySQL Tools Community                       31
mysql56-community/x86_64          MySQL 5.6 Community Server                 199
一,配置
 
 複製代碼//加入开机启动 
[root@iZ28gvqe4biZ ~]# systemctl enable mysqld
複製代碼//启动mysql服务进程
[root@iZ28gvqe4biZ ~]# systemctl start mysqld
Centos yum MySQL   
 複製代碼//重置密码
[root@iZ28gvqe4biZ ~]# mysql_secure_installation
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MySQL
      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!
In order to log into MySQL to secure it, we'll need the current
password for the root user.  If you've just installed MySQL, and
you haven't set the root password yet, the password will be blank,
so you should just press enter here.
Enter current password for root (enter for none): 
OK, successfully used password, moving on...
Setting the root password ensures that nobody can log into the MySQL
root user without the proper authorisation.
Set root password? [Y/n] y        [设置root用户密码]
New password: 
Re-enter new password: 
Password updated successfully!
Reloading privilege tables..
 ... Success!
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.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.
Remove anonymous users? [Y/n] y            [删除匿名用户]
 ... Success!
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? [Y/n] n            [禁止root远程登录]
 ... skipping.
By default, MySQL comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.
Remove test database and access to it? [Y/n] y       [删除test数据库]
 - Dropping test database...
ERROR 1008 (HY000) at line 1: Can't drop database 'test'; database doesn't exist
 ... Failed!  Not critical, keep moving...
 - Removing privileges on test database...
 ... Success!
Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.
Reload privilege tables now? [Y/n] y        [刷新权限]
 ... Success!
All done!  If you've completed all of the above steps, your MySQL
installation should now be secure.
Thanks for using MySQL!
Cleaning up...
示例:新建測試數據庫
 
 複製代碼//登录MYSQL(有ROOT权限)。这里我以ROOT身份登录
[root@iZ28gvqe4biZ ~]# mysql -u root -p
//修改访问权限,让其他计算机也能访问
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'yourpassword' WITH GRANT OPTION;
//首先为用户创建一个数据库hivemeta
mysql  > create database test;
mysql  > use test
//授权hdp用户拥有hivemeta数据库的所有权限。
mysql  > grant all privileges on *.* to cgq@"%" identified by "yckj" with grant option;
//刷新系统权限表
mysql  > flush privileges;
mysql  > use test;
//mysql/hive字符集问题
mysql  > alter database test character set latin1;
测试连接......
 RHEL / CentOS 完整移除 MySQL 伺服器
 
 以下文章會示範在 RHEL 及 CentOS 下完整移除 MySQL 伺服器, 如果 MySQL 的資料還有用, 在開始前務必要先備份 MySQL 的資料。
 
 首先檢查安裝在系統的 MySQL 相關套件, 可以用 rpm 或 yum 指令查看:
 
 
 複製代碼# rpm -qa | grep mysql
mysql-libs-5.1.73-5.el6_6.x86_64
mysql-server-5.1.73-5.el6_6.x86_64
mysql-5.1.73-5.el6_6.x86_64
或
 
 
 
 
 複製代碼# yum list installed | grep mysql
知道了安裝在系統的 MySQL 相關套件後, 用 YUM 移除:
 
 
 複製代碼# yum remove mysql-libs mysql-server mysql-client mysql
移除了 MySQL 的相關套件後, 接著是把資料庫目錄及 my.cnf 移除:
 
 
 複製代碼# rm -rf /var/lib/mysql/
# rm -rf /etc/my.cnf
這時已經完整地從系統移除 MySQL 了。
 參考文章
 https://www.jianshu.com/p/481763139ef2
 https://www.opencli.com/linux/rhel-centos-remove-mysql-server
 
 | 
 |