一、错误描述：
错误如标题：ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)。我用root@localhost授权登陆，然后给其中
一个用户授权，然后报如上错误：
[mysql@centos6-clone ~]$ mysql -u root -p
Enter password: 
Your MySQL connection id is 2
Server version: 5.6.25-log MySQL Community Server (GPL)
mysql>  grant all  on *.* to 'fi'@'127.0.0.1' identified by "fi";
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
mysql> exit
Bye
按理来说，root@localhost是最高权限。居然不能给其他人授权。1045错误是授权拒绝。怎么办？
二、错误分析
查看下root权限：
mysql> show grants;
+----------------------------------------------------------------------------------------------------------------------+
| Grants for root@localhost                                                                                            |
+----------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY PASSWORD '*E74858DB86EBA20BC33D0AECAE8A8108C56B17FA' |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION                                                         |
+----------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
我们看root@localhost 有权限：ALL PRIVILEGES，但是没有WITH GRANT OPTION 语句，就是别人授权的权限。所以，不能授权的原因是：
没有这个WITH GRANT OPTION 语句。
三、错误解决
知道原因了，解决问题就很简单了。用另外一个方式登录root@127.0.0.1,然后给root@localhost授权，这样root@localhost 就可以给其他用户
授权了。
[mysql@centos6-clone ~]$ mysql -uroot -p -h227.0.0.1
Enter password: 
mysql> SHOW GRANTS
    -> ;
+----------------------------------------------------------------------------------------------------------------------------------------+
| Grants for root@127.0.0.1                                                                                                              |
+----------------------------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'127.0.0.1' IDENTIFIED BY PASSWORD '*E74858DB86EBA20BC33D0AECAE8A8108C56B17FA' WITH GRANT OPTION |
+----------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql>  GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY PASSWORD '*E74858DB86EBA20BC33D0AECAE8A8108C56B17FA' WITH GRANT OPTION;
Query OK, 0 rows affected (0.00 sec)
mysql> exit
[mysql@centos6-clone ~]$ mysql -uroot -p
Enter password: 
mysql> grant all  on *.* to 'fo'@'%' identified by "fo";
Query OK, 0 rows affected (0.00 sec)