安装mysql

1.下载mysql源安装包

shell> wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm

2.安装mysql源

shell> yum localinstall mysql57-community-release-el7-8.noarch.rpm

3.检查mysql源是否安装成功

shell> yum repolist enabled | grep "mysql.*-community.*"

4.修改 vim /etc/yum.repos.d/mysql-community.repo源 ，改变默认安装的mysql版本。比如要安装5.6版本，将5.7源的enabled=1改成enabled=0。然后再将5.6源的enabled=0改成enabled=1即可。

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

5.安装MySQL

shell> yum install mysql-community-server

6.启动MySQL服务

shell> systemctl start mysqld

7.开机启动

shell> systemctl enable mysqld

shell> systemctl daemon-reload

8.修改root本地登录密码

1)查看mysql密码

shell> grep 'temporary password' /var/log/mysqld.log

2)连接mysql

shell> mysql -uroot -p

3)修改密码[注意：后面的分号一定要跟上]

mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass4!';

或者：

mysql> set password for 'root'@'localhost'=password('MyNewPass4!');

mysql> show variables like ‘%password%’;

9.添加远程登录用户

mysql> GRANT ALL PRIVILEGES ON *.* TO 'caoxiaobo'@'%' IDENTIFIED BY 'Caoxiaobo0917!' WITH GRANT OPTION;

10.设置密码安全规则

set global validate_password_policy=0;

set global validate_password_length=1;

11.刷新映射关系

flush privileges;

卸载mysql

yum方式安装的mysql

1、yum remove mysql mysql-server mysql-libs compat-mysql51

2、rm -rf /var/lib/mysql

3、rm /etc/my.cnf

查看是否还有mysql软件：

rpm -qa|grep mysql

如果存在的话，继续删除即可。

rpm方式安装的mysql

a)查看系统中是否以rpm包安装的mysql：

[root@localhost opt]# rpm -qa | grep -i mysql

MySQL-server-5.6.17-1.el6.i686

MySQL-client-5.6.17-1.el6.i686

b)卸载mysql

[root@localhost local]# rpm -e MySQL-server-5.6.17-1.el6.i686

[root@localhost local]# rpm -e MySQL-client-5.6.17-1.el6.i686

c)删除mysql服务

[root@localhost local]# chkconfig –list | grep -i mysql

[root@localhost local]# chkconfig –del mysql

d)删除分散mysql文件夹

[root@localhost local]# whereis mysql 或者 find / -name mysql

mysql: /usr/lib/mysql /usr/share/mysql

清空相关mysql的所有目录以及文件

rm -rf /usr/lib/mysql

rm -rf /usr/share/mysql

rm -rf /usr/my.cnf