一、卸载MySQL

卸载系统自带的mariadb

rpm -qa|grep mariadb
rpm -e mariadb-libs --nodeps
rpm -qa|grep mariadb

卸载MySQL

systemctl stop mysqld.service
rpm -qa | grep -i mysql  
yum remove mysql-community-libs-5.7.29-1.el7.x86_64 mysql-community-common-5.7.29-1.el7.x86_64 mysql-community-client-5.7.29-1.el7.x86_64 mysql-community-server-5.7.29-1.el7.x86_64
rpm -qa | grep -i mysql
find / -name mysql

rm -rf /etc/my.cnf
rm -rf /var/log/mysqld.log

二、安装MySQL

创建MySQL目录
```
mkdir /export/server/mysql
```
上传压缩包到该文件夹

解压压缩包

tar -xvf mysql-5.7.34-1.el7.x86_64.rpm-bundle.tar

执行安装

yum -y install libaio
rpm -ivh mysql-community-client-5.7.34-1.el7.x86_64.rpm mysql-community-common-5.7.34-1.el7.x86_64.rpm mysql-community-devel-5.7.34-1.el7.x86_64.rpm mysql-community-embedded-5.7.34-1.el7.x86_64.rpm mysql-community-embedded-compat-5.7.34-1.el7.x86_64.rpm mysql-community-embedded-devel-5.7.34-1.el7.x86_64.rpm mysql-community-libs-5.7.34-1.el7.x86_64.rpm mysql-community-libs-compat-5.7.34-1.el7.x86_64.rpm mysql-community-server-5.7.34-1.el7.x86_64.rpm

三、配置MySQL

初始化
```
mysqld --initialize
```
更改所属组
```
chown mysql:mysql /var/lib/mysql -R
```
启动MySQL
```
systemctl start mysqld.service
```
查看生成的临时root密码
```
cat  /var/log/mysqld.log
```
登录MySQL
```
mysql -uroot -p
临时root密码
```

修改root密码

# 更新用户密码，设置为123456
alter user user() identified by "123456";
# 选择数据库
use mysql;
# 授权
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY '123456' WITH GRANT OPTION;
FLUSH PRIVILEGES;

查看、开启、关闭mysql服务

# 查看mysql服务状态
systemctl status mysqld
# 关闭mysql服务
systemctl stop mysqld
# 查看mysql服务状态
systemctl status mysqld
# 开启mysql服务
systemctl start mysqld
# 查看mysql服务状态
systemctl status mysqld