①卸载系统预装 mariadb
rpm -e --nodeps mariadb-libs-1:5.5.56-2.el7.x86_64
注：MySQL 被 Oracle 收购，社区担心将来 MySQL 被 Oracle 关闭开源模式，和 Oracle 数据库一样变成商业化运作。所以社区开发了一个 MySQL 的社区版，内部和 MySQL 一样，只是名字不同，这就是 mariadb。但是我们当前在 Linux 系统中已经预装的 mariadb 只是一个残片，不能直接使用。所以还是要先卸载。
②安装服务器端程序
rpm -ivh /opt/MySQL-server-5.5.52-1.el6.x86_64.rpm
验证
[root@apple opt]# id mysql
uid=988(mysql) gid=982(mysql) 组=982(mysql)
③安装客户端程序
rpm -ivh /opt/MySQL-client-5.5.52-1.el6.x86_64.rpm
④启动 MySQL 服务
systemctl start mysql.service
⑤设置 root 用户密码
注意：这里的 root 用户是 MySQL 的 root 用户，不是 Linux 的 root 用户
[root@apple opt]# mysqladmin -u root password
New password:
Confirm new password:
⑥登录MySQL
[root@apple opt]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.5.52 MySQL Community Server (GPL)
Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test |
+--------------------+
4 rows in set (0.00 sec)
⑦客户端登录 MySQL 服务器
[1]被防火墙拦截的错误提示
通过关闭防火墙服务器解决
systemctl stop firewalld.service
systemctl disable firewalld.service
[2]被MySQL自己拒绝连接
[3]在 MySQL 服务器端设置允许任何主机地址访问
执行SQL语句
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'atguigu' WITH GRANT OPTION;
重启 MySQL 服务。下面是执行操作的参考：
[root@apple opt]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.5.52 MySQL Community Server (GPL)
Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> use mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select host,user,password from user;
+-----------+------+-------------------------------------------+
| host | user | password |
+-----------+------+-------------------------------------------+
| localhost | root | *453FDE92DF58E2DE1A51D27869CF3F1A69984B1B |
| apple | root | |
| 127.0.0.1 | root | |
| ::1 | root | |
| localhost | | |
| apple | | |
+-----------+------+-------------------------------------------+
6 rows in set (0.01 sec)
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'atguigu' WITH GRANT OPTION;
Query OK, 0 rows affected (0.00 sec)
mysql> select host,user,password,select_priv,update_priv from user;
+-----------+------+-------------------------------------------+-------------+-------------+
| host | user | password | select_priv | update_priv |
+-----------+------+-------------------------------------------+-------------+-------------+
| localhost | root | *453FDE92DF58E2DE1A51D27869CF3F1A69984B1B | Y | Y |
| apple | root | | Y | Y |
| 127.0.0.1 | root | | Y | Y |
| ::1 | root | | Y | Y |
| localhost | | | N | N |
| apple | | | N | N |
| % | root | *453FDE92DF58E2DE1A51D27869CF3F1A69984B1B | Y | Y |
+-----------+------+-------------------------------------------+-------------+-------------+
7 rows in set (0.00 sec)
重启MySQL服务
systemctl restart mysql.service
⑧解决字符乱码问题
[1]查看字符相关变量
mysql> show variables like "%char%";
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | latin1 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | latin1 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)
[2]准备MySQL配置文件
cp /usr/share/mysql/my-small.cnf /etc/my.cnf
[mysqld]
port = 3306
socket = /var/lib/mysql/mysql.sock
skip-external-locking
key_buffer_size = 16K
max_allowed_packet = 1M
table_open_cache = 4
sort_buffer_size = 64K
read_buffer_size = 256K
read_rnd_buffer_size = 256K
net_buffer_length = 2K
thread_stack = 128K
character-set-server=utf8
在[mysqld]部分的配置的最后添加 character-set-server=utf8
注意：别在 vim 的一般模式下直接粘贴！一定要进入编辑模式！
重启MySQL服务
systemctl restart mysql.service
查看字符集相关变量
mysql> show variables like "%char%";
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)
重新创建数据库、创建数据库表、插入中文字符数据验证。