# 检测
[root@localhost ~]# yum list installed | grep mysql

# 拆卸
[root@localhost ~]# yum -y remove mysql-libs.x86_64

[root@localhost ~]# yum install -y https://repo.mysql.com//mysql57-community-release-el7-11.noarch.rpm

#查看yum mysql仓库

[root@localhost ~]# ls /etc/yum.repos.d/ 

[root@localhost ~]# cat /etc/yum.repos.d/

　[root@localhost ~]# vim /etc/yum.repos.d/mysql-community.repo

# 修改配置文件

 [mysql57-community]

  name=MySQL 5.7 Community Server

  baseurl=http://repo.mysql.com/yum/mysql-5.7community/el/7/$basearch/  #这里修改成本地文件路径

  enabled=  # -开启 -关闭

  gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql # 设置成0不用检查

[root@localhost ~]# yum list | grep "mysql-community"

mysql-community-server.x86_64 5.7.-.el7 mysql57-community

mysql-community-client.x86_64 5.7.-.el7 mysql57-community

[root@localhost ~]# yum install mysql-community-client mysql-community-server -y
或
 yum install mysql-community-server 

#启动服务
[root@localhost ~]# systemctl start mysqld

　#查看服务

　[root@localhost ~]# systemctl status mysqld

mysqld.service - MySQL Server
  Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
  Active: active (running) since 三 2019-01-02 20:13:46 CST; 18s ago   #running 开启
  Docs: man:mysqld(8)
  http://dev.mysql.com/doc/refman/en/using-systemd.html
  Process: 8711 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
  Process: 8632 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
  Main PID: 8714 (mysqld)
  Tasks: 27
  CGroup: /system.slice/mysqld.service
   └─8714 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid

#重启服务

[root@localhost ~]# systemctl restart mysqld

#查看密码
[root@localhost ~]# grep 'temporary password' /var/log/mysqld.log
[root@localhost ~]# mysql -uroot -p
Enter password:

[root@localhost ~]# set global validate_password_policy=0;
[root@localhost ~]# set global validate_password_length=1;

[root@localhost ~]# ALTER USER 'root'@'localhost' IDENTIFIED BY '';

[root@localhost ~]# systemctl restart mysqld

[root@localhost ~]# mysql -uroot -p

 Enter password:

GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'your_root_password' WITH GRANT OPTION;  
FLUSH PRIVILEGES; 

[root@localhost ~]# systemctl stop firewalld                  #关闭当前防火墙

[root@localhost ~]# systemctl disable firewalld               #开机自动关闭

配置文件：/etc/my.cnf

日志文件：/var/log/mysqld.log

服务启动脚本：/usr/lib/systemd/system/mysqld.service

socket文件：/var/run/mysqld/mysqld.pid

　#(a)数据库目录 
　  /var/lib/mysql/

　#(b)配置文件
　　/usr/share /mysql（mysql.server命令及配置文件）

　#(c)相关命令 
　　/usr/bin（mysqladmin mysqldump等命令）

　#(d)启动脚本 
　　/etc/rc.d/init.d/（启动脚本文件mysql的目录）

#在[mysqld]的段中加上一句：skip-grant-tables 保存并且退出vi。

mysql  -u root

update mysql.user set authentication_string=password('123qwe') where user='root' and Host = 'localhost';

flush privileges