报错条目：
ERROR 1045 (28000): Access denied foruser 'mhauser'@'localhost' (using password: YES)
ERROR 1045 (28000): Access denied foruser 'root'@'localhost' (using password: YES)
ERROR 1045 (28000): Access denied foruser 'root'@'192.168.88.130' (using password: NO)
解决方法：
update user set host='%' whereuser='xxx';
GRANT ALL ON *.* TO 'xxx'@'localhost'IDENTIFIED BY '888888';
1、普通账户无法登录
[root@www ~]# mysql -u mhauser -p
Enter password:
ERROR 1045 (28000): Access denied for user'mhauser'@'localhost' (using password: YES)
出现该错误的原因为给mhauser分配可以登录的主机时使用SQL：
mysql> GRANT ALL ON *.* TO 'mhauser'@'192.168.88.%'IDENTIFIED BY 'mhapass';
允许远程登录的主机为"192.168.88.%"，在同一台服务器登录时主机识别为localhost，故无法登录。
此处使用
1）：updateuser set host='%' where user='mhauser';
2）：GRANTALL ON *.* TO 'mhauser'@'localhost' IDENTIFIED BY'888888';
即可解决问题
方法1演示：
mysql> use mysql
更新密码，可不操作
mysql> update user set password=password('888888')where user='mhauser';
Query OK, 1 row affected (0.05 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> show full processlist;
+----+----------+----------------------+---------+-------------+------+----------------------------------------------------------------+-----------------------+
| Id | User | Host | db | Command | Time | State |Info |
+----+----------+----------------------+---------+-------------+------+----------------------------------------------------------------+-----------------------+
| 7 | root | localhost | hellodb | Sleep | 6544 | | NULL |
| 9 | root | localhost | mydb | Sleep | 6897 | | NULL |
| 16 | root | localhost | mysql |Query | 0 | NULL | show full processlist |
| 18 | repluser | 192.168.88.130:45967 | NULL | Binlog Dump | 49 |Has sent all binlog to slave; waiting for binlog to be updated |NULL |
+----+----------+----------------------+---------+-------------+------+----------------------------------------------------------------+-----------------------+
4 rows in set (0.00 sec)
mysql> flushprivileges;
Query OK, 0 rows affected (0.12 sec)
查看mhauser被赋予的权限
mysql> select * from user whereuser='mhauser'\G
*************************** 1. row***************************
Host: 192.168.88.% <--可以发现，host为192.168.88.%
User: mhauser
Password: *DA28842831B3C40F4BC1D3C76CF9AD8CBFDAE1CB
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
Create_priv: Y
Drop_priv: Y
Reload_priv: Y
Shutdown_priv: Y
Process_priv: Y
File_priv: Y
Grant_priv: N <--不具备授权权限
References_priv: Y
Index_priv: Y
Alter_priv: Y
Show_db_priv: Y
Super_priv: Y
Create_tmp_table_priv: Y
Lock_tables_priv: Y
Execute_priv: Y
Repl_slave_priv: Y
Repl_client_priv: Y
Create_view_priv: Y
Show_view_priv: Y
Create_routine_priv: Y
Alter_routine_priv: Y
Create_user_priv: Y
Event_priv: Y
Trigger_priv: Y
ssl_type:
ssl_cipher:
x509_issuer:
x509_subject:
max_questions: 0
max_updates: 0
max_connections: 0
max_user_connections:0
1 row in set (0.00 sec)
重设能够登录的主机,%即为所有。
mysql> update user set host='%' whereuser='mhauser';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
清空缓存中的权限，刷新权限
mysql> flushprivileges;
Query OK, 0 rows affected (0.00 sec)
查看字段值是否修改成功
mysql> select host, user, Password, grant_priv fromuser;
+---------------+----------+-------------------------------------------+------------+
| host | user | Password | grant_priv |
+---------------+----------+-------------------------------------------+------------+
| localhost | root | | Y |
| www.field.com | root | | Y |
| 127.0.0.1 | root | | Y |
| 192.168.%.% |repluser | *00E247AC5F9AF26AE0194B41E1E769DEE1429A29 |N |
| 192.168.88.% | repluser |*D98280F03D0F78162EBDBB9C883FC01395DEA2BF | N |
| % | mhauser |*DA28842831B3C40F4BC1D3C76CF9AD8CBFDAE1CB | N |
+---------------+----------+-------------------------------------------+------------+
6 rows in set (0.18 sec)
测试登录，成功
[root@www ~]# mysql -u mhauser -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or\g.
Your MySQL connection id is 23
Server version: 5.1.73-log Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates.All rights reserved.
Oracle is a registered trademark of Oracle Corporationand/or its
affiliates. Other names may be trademarks of theirrespective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear thecurrent input statement.
mysql>
方法2演示：
把host改回'192.168.88.%'，令其仍旧不能登录。
mysql> update user set host='192.168.88.%' whereuser='mhauser';
Query OK, 0 rows affected (0.01 sec)
Rows matched: 1 Changed: 0 Warnings: 0
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> select host, user, Password, grant_priv fromuser;
+---------------+----------+-------------------------------------------+------------+
| host | user | Password | grant_priv |
+---------------+----------+-------------------------------------------+------------+
| localhost | root | | Y |
| www.field.com | root | | Y |
| 127.0.0.1 | root | | Y |
| 192.168.%.% |repluser | *00E247AC5F9AF26AE0194B41E1E769DEE1429A29 |N |
| 192.168.88.% | repluser |*D98280F03D0F78162EBDBB9C883FC01395DEA2BF | N |
| 192.168.88.% | mhauser |*DA28842831B3C40F4BC1D3C76CF9AD8CBFDAE1CB | N |
+---------------+----------+-------------------------------------------+------------+
6 rows in set (0.00 sec)
mysql> exit
Bye
[root@www ~]# mysql -u mhauser -p888888
ERROR 1045 (28000): Access denied for user'mhauser'@'localhost' (using password: YES)
此处采用grant方式授权登录
[root@www ~]# mysql -u root
Welcome to the MySQL monitor. Commands end with ; or\g.
mysql> use mysql
mysql> GRANT ALL ON *.* TO 'mhauser'@'localhost'IDENTIFIED BY '888888';
Query OK, 0 rows affected (0.04 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> select host, user, Password, grant_priv fromuser;
+---------------+----------+-------------------------------------------+------------+
| host | user | Password | grant_priv |
+---------------+----------+-------------------------------------------+------------+
| localhost | root | | Y |
| www.field.com | root | | Y |
| 127.0.0.1 | root | | Y |
| localhost | mhauser |*DA28842831B3C40F4BC1D3C76CF9AD8CBFDAE1CB | N |
| 192.168.%.% |repluser | *00E247AC5F9AF26AE0194B41E1E769DEE1429A29 |N |
| 192.168.88.% | repluser |*D98280F03D0F78162EBDBB9C883FC01395DEA2BF | N |
| 192.168.88.% | mhauser |*DA28842831B3C40F4BC1D3C76CF9AD8CBFDAE1CB | N |
+---------------+----------+-------------------------------------------+------------+
localhost | mhauser <--可见以添加该条目
7 rows in set (0.00 sec)
mysql> exit
Bye
测试登录，成功。
[root@www ~]# mysql -u mhauser -p888888
Welcome to the MySQL monitor. Commands end with ; or\g.
Your MySQL connection id is 35
Server version: 5.1.73-log Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates.All rights reserved.
Oracle is a registered trademark of Oracle Corporationand/or its
affiliates. Other names may be trademarks of theirrespective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear thecurrent input statement.
mysql>
2、使用root无法远程登录
该错误原因则是root不具备远程登录其他服务器的权限
[root@test ~]# mysql -u root -h 192.168.88.131
ERROR 1045 (28000): Access denied for user'root'@'192.168.88.130' (using password: NO)
[root@test ~]# mysql -u root
mysql> select host, user, Password, grant_priv fromuser;
+----------------+----------+-------------------------------------------+------------+
| host | user | Password | grant_priv |
+----------------+----------+-------------------------------------------+------------+
| localhost | root | | Y |
| test.field.com | root | | Y |
| 127.0.0.1 | root | | Y |
| % | field | | N |
| 192.168.88.% |repluser | *D98280F03D0F78162EBDBB9C883FC01395DEA2BF |N |
| % | mhauser |*DA28842831B3C40F4BC1D3C76CF9AD8CBFDAE1CB | N |
+----------------+----------+-------------------------------------------+------------+
6 rows in set (0.00 sec)
由上表可见，root账户能登录的主机为localhost，test.field.com，127.0.0.1,。
显然，不能登录的原因类似于上述mhauser账户，root账户不具备远程登录其它MySQL服务器的权限，
使用以下任意一个命令即可解决问题：
update user set host='%' whereuser='root';
GRANT ALL ON *.* TO 'root'@'%'IDENTIFIED BY '888888';
当然笔者强烈建议不要使用root远程登录其他MySQL服务器。