记录CentOS7.X版本下安装MySQL5.7数据库

 设置rpm下载目录在/opt目录下新建一个目录存放mysql

cd /opt
sudo mkdir mysql

 下载MySQL的源

wget http://repo.mysql.com/mysql57-community-release-el7-8.noarch.rpm

 如果在这之前没有提示-bash: wget: command not found，那么还得先安装wget

sudo yum install wget

 安装MySQL的rpm

sudo rpm -ivh mysql57-community-release-el7-8.noarch.rpm

 安装MySQL

sudo yum install mysql-server

 在这步中只需要一直y然后回车就行，数据库就安装好了，现在进行连接：

mysql -uroot -p
root
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

 这是/var/lib/mysql权限问题，修改MySQL权限为当前用户

sudo chown -R xxx:xxx /var/lib/mysql

 xxx为当前的用户名以及所属组
 重启MySQL服务

service mysqld restart

 密码输入root即可
 如果还不行的话通过这个命令获得初始密码

cat /var/log/mysqld.log  | grep password

 其中A temporary password is generated for root@localhost: bGlY?13TtFyX–：后面的就是初始密码；登陆进去之后先不做其他操作，作如下操作：

set global validate_password_policy=0;
set global validate_password_length=4;

 设置密码

alter user 'root'@'localhost' identified by 'root';

 自此CentOS安装MySQL5.7就完美安装了

 mysql -uroot -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.20 MySQL Community Server (GPL)

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