MySQ彻底删除与安装配置

彻底删除

1.查看 MySQL 安装了哪些东西

rpm -qa |grep -i mysql

 2.卸载

yum remove mysql-community-common-5.7.20-1.el7.x86_64
yum remove mysql-community-client-5.7.20-1.el7.x86_64
yum remove mysql57-community-release-el7-11.noarch
yum remove mysql-community-libs-5.7.20-1.el7.x86_64
yum removemysql-community-server-5.7.20-1.el7.x86_64

mariadb 也要删除

rpm -qa | grep mariadb

rpm -e --nodeps 包名称（比如：rpm -e --nodeps mariadb-libs-5.5.44-2.el7.centos.x86_64）

3.查看是否卸载完成

 4.查找 MySQL 相关目录

find / -name mysql

5.删除相关目录

rm -rf 

 6.删除  /etc/my.cnf 

rm -rf /etc/my.cnf

7.删除 /var/log/mysqld.log （如果不删除这个文件，会导致新安装的 MySQL 无法生成新密码，导致无法登陆）

rm -rf /var/log/mysqld.log

安装

1.增加官方的 yum 源（以5.6 为例）

创建并编辑 mysql-community.repo 文件

vi /etc/yum.repos.d/mysql-community.repo

将以下内容粘贴进去并保存

[mysql56-community]
name=MySQL 5.6 Community Server
baseurl=http://repo.mysql.com/yum/mysql-5.6-community/el/7/$basearch/
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql

注意：gpgcheck是GPG加密校验，官方文档中值为1，但check会报错误，所以这里改为0跳过检查，对安装无影响。

2.安装 MySQL

sudo yum -y install mysql-community-server

效果如下：

Installed:
  mysql-community-server.x86_64 0:5.6.41-2.el7                                     

Dependency Installed:
  mysql-community-client.x86_64 0:5.6.41-2.el7                                     
  mysql-community-common.x86_64 0:5.6.41-2.el7                                     
  mysql-community-libs.x86_64 0:5.6.41-2.el7                                       
  net-tools.x86_64 0:2.0-0.22.20131004git.el7                                      
  perl-DBI.x86_64 0:1.627-4.el7                                                    
  perl-Net-Daemon.noarch 0:0.48-5.el7                                              
  perl-PlRPC.noarch 0:0.2020-14.el7                                                

Complete!

3.启动 MySQL 并允许 MySQL 自启

sudo systemctl start mysqld
sudo systemctl enable mysqld

配置编码

1.进入 MySQL 查看编码

show variables like '%character%';

结果如下：

mysql> show variables like '%character%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | latin1                     |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | latin1                     |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+

2.修改编码

sudo vi /etc/my.cnf
# 然后在 [mysqld] 下添加 character-set-server=utf8

sudo vi /etc/my.cnf.d/client.cnf
# 然后在 [client] 下添加 default-character-set=utf8

3.再次查看编码：

mysql> show variables like '%character%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+