安装MySQL 5.7.20

shell> cd /usr/local

shell> groupadd mysql

shell> useradd -g mysql mysql

shell> tar xzvf mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz

shell> cd mysql-5.7.20-linux-glibc2.12-x86_64

这里注意了，以前的版本是有一个my.cnf文件，这个版本不要这个了

如果存在就把它删除吧，否则会出现各种错误

shell> rm -rf /etc/my.cnf

shell> cd /usr/local

shell> ln -s mysql-5.7.20-linux-glibc2.12-x86_64 mysql

shell> cd /usr/local/mysql

shell> chown -R mysql .

shell> chgrp -R mysql .

shell> mkdir /usr/local/mysql/data

shell> /usr/local/mysql/bin/mysqld --initialize --user=mysql --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data

出现以下几个[Warning]不用管它，只要没有[ERROR] 就是安装成功了

[Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).

[Warning] InnoDB: New log files created, LSN=45790

[Warning] InnoDB: Creating foreign key constraint system tables.

[Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: a4d71248-c432-11e7-8eab-00163e002e4a.

[Warning] Gtid table is not ready to be used. Table ‘mysql.gtid_executed’ cannot be opened.

[Note] A temporary password is generated for root@localhost: =MqLUlnme6hh

注意了，上面最后一行产一个随机密码，冒号后面的都是密码，我的密码则是=MqLUlnme6hh

这个随机密码第一次登录的时候需要用到

shell> chown -R root .

shell> chown -R mysql data

启动MySQL

shell> cd /usr/local/mysql

shell> bin/mysqld_safe --user=mysql &

登录并更改密码

shell> /usr/local/mysql/bin/mysql -uroot -p

这时提示输入password，输入上面的随机密码

用随机密码登录后，必须要更改密码，否则不能进行任何操作，更改密码：

mysql> set password = password('a123456');

mysql> exit;

关闭MySQL服务

shell> /usr/local/mysql/bin/mysqladmin -u root -p shutdown

shell> Enter password:

输入密码回车就关闭数据库

编辑PATH搜索路径

shell> vi /etc/profile

在profile文件末尾增加两行

PATH=/usr/local/mysql/bin:/usr/local/mysql/lib:$PATH

export PATH

使PATH搜索路径立即生效：

shell> source /etc/profile

开机自动启动：

shell> cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysql

shell> chkconfig --add mysql

手动启动：以root身份执行：

shell> /usr/local/mysql/bin/mysqld_safe --user=mysql &

#赋予root用户所有权限，远程登录密码是123456

grant all privileges on *.* to 'root'@'%' identified by 'a12345678.';(了解下：grant用法 )

#开放3306端口并重启防火墙

firewall-cmd --permanent --add-port=3306/tcp(这边都是错的)

firewall-cmd --reload