MySql ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

For security reason mysql -u root wont work untill you pass -p in command so try with below way

 mysql -u root -p[Enter]
 //enter your localhost password

mysql -u root -p;

And mysql will ask for the password

Just to confirm: You are sure you are running MySQL 5.7, and not MySQL 5.6 or earlier version. And the plugin column contains "mysql_native_password". (Before MySQL 5.7, the password hash was stored in a column named password. Starting in MySQL 5.7, the password column is removed, and the password has is stored in the authentication_string column.) And you've also verified the contents of authentication string matches the return from PASSWORD('mysecret'). Also, is there a reason we are using DML against the mysql.user table instead of using the SET PASSWORD FOR syntax? – spencer7593

So Basically Just make sure that the Plugin Column contains "mysql_native_password".

Not my work but I read comments and noticed that this was stated as the answer but was not posted as a possible answer yet.