SQLSTATE [HY000] [1698]拒绝访问用户'root'@'localhost'

I just installed Ubuntu 16.04 and installed web server on it. Everything works well, but I cannot access database. Even if I create new user and grant all privileges, I can't create database In PHP I'm getting this error:

SQLSTATE[HY000] [1698] Access denied for user 'root'@'localhost'

When I try to login in terminal, it works, but in PHP and phpmyadmin don't.

PHP Code:

protected $host = '127.0.0.1';
protected $db = 'dbname';
protected $name = 'root';
protected $pass = 'root';
protected $conn;
private static $settings = array(
    PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8'
);

public function __construct() {
    try {
        $this->conn = new PDO("mysql:host=$this->host;dbname=$this->db", $this->name, $this->pass, self::$settings);
    } catch (PDOException $e) {
        echo $e->getMessage();
    }
}

Users for mysql and for server are 2 different things, look how to add user to database and login with these credentials

MySQL makes a difference between "localhost" and "127.0.0.1".

It might be possible that 'root'@'localhost' is not allowed because there is an entry in the user table that will only allow root login from 127.0.0.1.

This could also explain why some application on your server can connect to the database and some not because there are different ways of connecting to the database. And you currently do not allow it through "localhost".

Turns out you can't use the root user in 5.7 anymore without becoming a sudoer. That means you can't just run mysql -u root anymore and have to do sudo mysql -u root instead.

That also means that it will no longer work if you're using the root user in a GUI (or supposedly any non-command line application). To make it work you'll have to create a new user with the required privileges and use that instead.

See this answer for more details.

These steps worked for me on several Systems using Ubuntu 16.04, Apache 2.4, MariaDB, PDO

log into MYSQL as root
```
mysql -u root
```

Grant privileges. To a new user execute:

CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON *.* TO 'newuser'@'localhost';
FLUSH PRIVILEGES;

UPDATE for Google Cloud Instances

MySQL on Google Cloud seem to require an alternate command (mind the backticks).

GRANT ALL PRIVILEGES ON `%`.* TO 'newuser'@'localhost';

bind to all addresses:
The easiest way is to comment out the line in your /etc/mysql/mariadb.conf.d/50-server.cnf or /etc/mysql/mysql.conf.d/mysqld.cnf file, depending on what system you are running:
```
#bind-address = 127.0.0.1 
```
exit mysql and restart mysql
```
exit
service mysql restart
```

By default it binds only to localhost, but if you comment the line it binds to all interfaces it finds. Commenting out the line is equivalent to bind-address=*.

To check the binding of mysql service execute as root:

netstat -tupan | grep mysql

Maybe a bit late, but I found this answer looking over the internet. It could help others with the same problem.

$sudo mysql -u root
[mysql] use mysql;
[mysql] update user set plugin='' where User='root';
[mysql] flush privileges;
[mysql] \q

Now you should be able to log in as root in phpmyadmin.

(Found here.)

With mysql Ver 14.14 Distrib 5.7.22 the update statement is now:

update user set authentication_string=password('1111') where user='root';

To create user for phpMyAdmin :

sudo mysql -p -u root

Now you can add a new MySQL user with the username of your choice.

CREATE USER 'USERNAME'@'%' IDENTIFIED BY 'PASSWORD';

And finally grant superuser privileges to the user you just created.

GRANT ALL PRIVILEGES ON *.* TO 'USERNAME'@'%' WITH GRANT OPTION;

For any question, please leave a comment

Just Create New User for MySQL do not use root. there is a problem its security issue

sudo mysql -p -u root

CREATE USER 'troy121'@'%' IDENTIFIED BY 'mypassword123';

GRANT ALL PRIVILEGES ON *.* TO 'magento121121'@'%' WITH GRANT OPTION;

and grant privileges to access "." and "@" "%" any location not just only 'localhost'

exit;

if you want to see your privilege table SHOW GRANTS; & Enjoy.