这招对我很管用:

mysql --user=root mysql
CREATE USER 'some_user'@'%' IDENTIFIED BY 'some_pass';
GRANT ALL PRIVILEGES ON *.* TO 'some_user'@'%' WITH GRANT OPTION;
FLUSH PRIVILEGES;

我建议删除MySQL连接-

这是MySQL 5.5版。如果你的版本不同，请相应地更改第一行。

sudo apt-get purge mysql-server mysql-client mysql-common mysql-server-core-5.5 mysql-client-core-5.5
sudo rm -rf /etc/mysql /var/lib/mysql
sudo apt-get autoremove
sudo apt-get autoclean

然后再次安装，但是这次你自己设置root密码。 这将节省很多精力。

sudo apt-get update
sudo apt-get install mysql-server

对于那些在macOS上安装最新MariaDB并遵循MariaDB文档中的本教程的用户，请运行:

sudo mariadb-secure-installation

而不是只给出mariadb-secure-installation命令。否则，运气不好，尽管出现错误提示:

In order to log into MariaDB to secure it, we'll need the current
password for the root user. If you've just installed MariaDB, and
haven't set the root password yet, you should just press enter here.

Enter current password for root (enter for none):
ERROR 1698 (28000): Access denied for user 'root'@'localhost'
Enter current password for root (enter for none):
ERROR 1698 (28000): Access denied for user 'root'@'localhost'
Enter current password for root (enter for none):
Aborting!

你想用root用户访问MySQL，但是你没有提供root用户的正确密码。

如果你需要为root用户设置一个新密码，MySQL的网站上有很多关于如何做的文档:B.3.3.2如何重置root用户密码

我不会在这里展示这个过程，因为上面链接的MySQL文档是清晰而简洁的。

首先

sudo mysql -u root -p

SHOW VARIABLES LIKE 'validate_password%';

我们会看到这样的东西:

+--------------------------------------+--------+
| Variable_name                        | Value  |
+--------------------------------------+--------+
| validate_password.check_user_name    | ON     |
| validate_password.dictionary_file    |        |
| validate_password.length             | 8      |
| validate_password.mixed_case_count   | 1      |
| validate_password.number_count       | 1      |
| validate_password.policy             | MEDIUM |
| validate_password.special_char_count | 1      |
+--------------------------------------+--------+

我们需要改变这些行:

validate_password.length validate_password.number_count validate_password.policy validate_password.special_char_count

SET GLOBAL validate_password.policy=LOW;
SET GLOBAL validate_password.length=4;
SET GLOBAL validate_password.number_count=0;
SET GLOBAL validate_password.special_char_count=0;

SHOW VARIABLES LIKE 'validate_password%';

我们将看到:

+--------------------------------------+-------+
| Variable_name                        | Value |
+--------------------------------------+-------+
| validate_password.check_user_name    | ON    |
| validate_password.dictionary_file    |       |
| validate_password.length             | 4     |
| validate_password.mixed_case_count   | 1     |
| validate_password.number_count       | 0     |
| validate_password.policy             | LOW   |
| validate_password.special_char_count | 0     |
+--------------------------------------+-------+

现在从MySQL客户端退出:

exit;
sudo mysql -u root -p

现在你可以写密码了，四个或四个以上的字母。

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'new-password';

exit;

sudo mysql -u root -p

数据库中有root用户的新密码;

这适用于我的mysql版本15.1:

$ sudo mysql

MariaDB [mysql]> use mysql;
MariaDB [mysql]> set password for 'root'@'localhost' = password('YOUR_ROOT_PASSWORD_HERE');
MariaDB [mysql]> flush privileges;
MariaDB [mysql]> quit

以“root”身份登录

mysql -u root -p

归功于Raoul HATTERER