title: unable to reset mysql 'root' password
body: <p>I have installed mysql 5.7.18. After installation the password of <code>root</code> user is <code>null</code>.
  I have tried <code>mysql_secure_instattation</code> and following queries to reset ther password.</p>
  
  <pre><code>ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyPassword';
  </code></pre>
  
  <p>and</p>
  
  <pre><code>UPDATE mysql.user
      SET authentication_string = PASSWORD('MyPassword'), password_expired = 'N'
      WHERE User = 'root' AND Host = 'localhost';
  FLUSH PRIVILEGES;
  </code></pre>
  
  <p>These methods executed successfully but still mysql root user is connecting <code>NULL</code> password.
  What should I do ?</p>