Access denied for user ''@'localhost' to database 'mysql'

修改my.ini   mysqld后加skip-grant-tables

1. 使用不验证的状态登陆

2.  \mysql\bin>mysql -u -root

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.38-log MySQL Community Server (GPL)

Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

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

3. mysql> use mysql
Database changed

4. mysql> update user set password=password("123456")where user="root";
Query OK, 2 rows affected (0.00 sec)
Rows matched: 3  Changed: 2  Warnings: 0

5. mysql> delete from user where user ='';
Query OK, 1 row affected (0.00 sec)

6. mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> quit