Ubuntu18.04(linux)安装MySQL的方法步骤

安装

mysql

sudo apt-get --purge remove mysql-server mysql-common mysql-client
sudo apt-get install mysql-server mysql-common mysql-client

mysqladmin -u root password your-new-password
sudo /etc/init.d/mysql restart

mariadb

apt-get install mariadb-server

字符集修改utf8

如果装的mariadb, 默认字符集已经是utf8了。mysql则不是

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/ |
+--------------------------+----------------------------+

mysql> show variables like 'collation%';
+----------------------+-------------------+
| Variable_name    | Value       |
+----------------------+-------------------+
| collation_connection | utf8_general_ci  |
| collation_database  | latin1_swedish_ci |
| collation_server   | latin1_swedish_ci |
+----------------------+-------------------+

修改字符集：

sudo vim /etc/mysql/my.cnf

添加以下内容

[mysqld]
collation-server = utf8_unicode_ci
init-connect='SET NAMES utf8'
character-set-server = utf8

重启：

service mysql restart

登录权限问题

Ubuntu18.04 安装mysql或者mariadb之后，发现普通用户和远程都没有权限连接。

ERROR 1045: Access denied for user: 'root@localhost' (Using
password: YES)

修改了密码也不对。然后sudo mysql -u root即可登录。这显然不是我们想要的。

解决方案

删除root，重新创建用户。

首先，登录

sudo mysql -u root

然后查看当前用户

SELECT User,Host FROM mysql.user;
+------------------+-----------+
| User       | Host   |
+------------------+-----------+
| admin      | localhost |
| debian-sys-maint | localhost |
| magento_user   | localhost |
| mysql.sys    | localhost |
| root       | localhost |

删除root账号

mysql> DROP USER 'root'@'localhost';
Query OK, 0 rows affected (0,00 sec)

重新创建root：

mysql> CREATE USER 'root'@'%' IDENTIFIED BY '123456';
Query OK, 0 rows affected (0,00 sec)

授权

mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION;
Query OK, 0 rows affected (0,00 sec)

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0,01 sec)

关于重置密码

host为%时允许远程登录

SET PASSWORD FOR root@'localhost' = PASSWORD('password');

or

UPDATE mysql.user SET Password=PASSWORD('newpwd') WHERE User='root';

or

USE mysql
UPDATE user SET Password = PASSWORD('newpwd')
WHERE Host = 'localhost' AND User = 'root';

允许任何地方登录

USE mysql
UPDATE user SET Password = PASSWORD('newpwd')
WHERE Host = '%' AND User = 'root';

参考
https://askubuntu.com/questions/766334/cant-login-as-mysql-user-root-from-normal-user-account-in-ubuntu-16-04
https://help.ubuntu.com/community/MysqlPasswordReset