安装mariadb，默认是无密码的，但一般是指要设置密码的。在设置密码时出现各种问题，可能还是不太明白其原理。

一下我尝试了两种方法，但都失败了。下面这两个是我尝试的方法：

一、网上最多的方法是

1、输入下面的指令

mysqladmin -u root -p password newpassword

但是我已输入提示输入密码，我输入密码了但提示错误，见下

[root@localhost sakila]# mysqladmin -u root -p password newpasswd

Enter password:

mysqladmin: connect to server at 'localhost' failed

error: 'Access denied for user 'root'@'localhost' (using password: YES)'

2、停掉数据库服务

systemctl stop mariadb.service

3、对所有的表设置成无密码登陆。

mysqld_safe --skip-grant-tables &

执行完这条语句提示一下错误

[root@localhost sakila]# mysqld_safe --skip-grant-tables &

[1] 14275

[root@localhost sakila]# 150424 10:13:41 mysqld_safe Logging to '/var/log/mariadb/mariadb.l

og'.150424 10:13:41 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql

4、尝试退出数据库，然后重启服务，再进入

[root@localhost sakila]# systemctl restart mariadb.service

[root@localhost sakila]# mysqladmin -u root -p password 'passwd'

Enter password:

mysqladmin:

You cannot use 'password' command as mysqld runs

with grant tables disabled (was started with --skip-grant-tables).

Use: "mysqladmin flush-privileges password '*'" instead

二、正确的操作

1、进到数据库进行操作

[root@localhost etc]# mysql

Welcome to the MariaDB monitor. Commands end with ; or \g.

Your MariaDB connection id is 7

Server version: 5.5.41-MariaDB MariaDB Server

Copyright (c) 2000, 2014, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> mysql

-> ;

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds

to your MariaDB server version for the right syntax to use near 'mysql' at line 1MariaDB [(none)]> update user set password=password("123456")where user='root';

ERROR 1046 (3D000): No database selected

2、选择数据库

MariaDB [(none)]> 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

修改密码

UPDATE user SET authentication_string=PASSWORD('aaaAAA111') WHERE user='root';

FLUSH PRIVILEGES;