Linux mysql 5.6： ERROR 1045 (28000): Access denied for user root@localhost (using password: NO)，28000denied

Linux mysql 5.6： ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)，28000denied

案例環境：

             操作系統 ：Red Hat Enterprise Linux Server release 5.7 (Tikanga) 64 bit

          數據庫版本 : Mysql 5.6.19 64 bit

案例介紹：

今天開始學習mysql，遂先安裝了Mysql 5.6.19 64bit 版本的數據庫，結果安裝成功了，但是使用root登錄時遇到了ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)錯誤. 如下所示

[root@DB-Server tmp]# rpm -ivh MySQL-server-5.6.19-1.rhel5.x86_64.rpm 

Preparing...                ########################################### [100%]

   1:MySQL-server           ########################################### [100%]

[root@DB-Server tmp]# rmp -ivh MySQL-client-5.6.19-1.rhel5.x86_64.rpm 

-bash: rmp: command not found

[root@DB-Server tmp]# rpm -ivh MySQL-client-5.6.19-1.rhel5.x86_64.rpm 

Preparing...                ########################################### [100%]

   1:MySQL-client           ########################################### [100%]

[root@DB-Server tmp]# /etc/rc.d/init.d/mysql status

MySQL is not running[FAILED]

[root@DB-Server tmp]# /etc/rc.d/init.d/mysql start

Starting MySQL.[  OK  ]

[root@DB-Server tmp]# mysql -u root -p

Enter password: 

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

[root@DB-Server tmp]# mysql -u root mysql

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

安裝過程中沒有設置過root密碼，不清楚root密碼，搜索了網上一些資料，大致有下面一些情況：

1：有些博客說root的隨機密碼位於/root/.mysql_secret中，但是我這個版本根本沒有/root/.mysql_secret文件。搜索到一篇文章，大意如下所示（沒有確認）。到現在也沒有明白，我這個版本為什麼沒有生成這個文件？

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO) :表示沒有生成root的臨時密碼

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES) :表示生成了root的臨時密碼。

2：有些資料說root的默認密碼為空，經過確認那是以前的老版本，Mysql 5.6及以後版本出處於安全考慮，root密碼已經不為空了。

另外，我在官網論壇居然發現有很多人遇到類似問題ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

解決方法：

首先停掉mysql服務器

[root@DB-Server init.d]# /etc/rc.d/init.d/mysql stop

 Shutting down MySQL..[ OK ]

然後使用mysqld_safe命令在啟動mysql，更新root賬號的密碼

--skip-grant-tables：不啟動grant-tables(授權表),跳過權限控制。

--skip-networking ：跳過TCP/IP協議，只在本機訪問(從網上有些資料看，這個選項不是必須的。可以不用)

[root@DB-Server init.d]# mysqld_safe --user=mysql --skip-grant-tables --skip-networking &

[2] 9396

[root@DB-Server init.d]# 140722 14:59:46 mysqld_safe Logging to '/var/lib/mysql/DB-Server.err'.

140722 14:59:46 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql

執行上面命令後，此會話窗口會出現無反應的狀態，需要使用CTRL+C中斷會話，檢查/var/lib/mysql/DB-Server.err日志，發現也無其它異常信息。沒有弄明白該會話窗口為啥會出現無響應狀態。

tail -200 /var/lib/mysql/DB-Server.err | more

2014-07-22 14:59:41 9346 [Note] Shutting down plugin 'binlog'

2014-07-22 14:59:41 9346 [Note] /usr/sbin/mysqld: Shutdown complete

140722 14:59:41 mysqld_safe mysqld from pid file /var/lib/mysql/DB-Server.pid ended

140722 14:59:46 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql

2014-07-22 14:59:47 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timesta

mp server option (see documentation for more details).

2014-07-22 14:59:47 9516 [Note] Plugin 'FEDERATED' is disabled.

2014-07-22 14:59:47 9516 [Note] InnoDB: Using atomics to ref count buffer pool pages

2014-07-22 14:59:47 9516 [Note] InnoDB: The InnoDB memory heap is disabled

2014-07-22 14:59:47 9516 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins

2014-07-22 14:59:47 9516 [Note] InnoDB: Compressed tables use zlib 1.2.3

2014-07-22 14:59:47 9516 [Note] InnoDB: Using Linux native AIO

2014-07-22 14:59:47 9516 [Note] InnoDB: Using CPU crc32 instructions

2014-07-22 14:59:47 9516 [Note] InnoDB: Initializing buffer pool, size = 128.0M

2014-07-22 14:59:47 9516 [Note] InnoDB: Completed initialization of buffer pool

2014-07-22 14:59:47 9516 [Note] InnoDB: Highest supported file format is Barracuda.

2014-07-22 14:59:47 9516 [Note] InnoDB: 128 rollback segment(s) are active.

2014-07-22 14:59:47 9516 [Note] InnoDB: Waiting for purge to start

2014-07-22 14:59:47 9516 [Note] InnoDB: 5.6.19 started; log sequence number 1626087

2014-07-22 14:59:47 9516 [Note] /usr/sbin/mysqld: ready for connections.

Version: '5.6.19'  socket: '/var/lib/mysql/mysql.sock'  port: 0  MySQL Community Server (GPL)

[root@DB-Server init.d]# mysql -u root mysql

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 1

Server version: 5.6.19 MySQL Community Server (GPL)

Copyright (c) 2000, 2014, 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.

mysql> select Host, User, Password,password_expired

    -> from user

    -> where user='root' and host='root' or host='localhost';

+-----------+------+-------------------------------------------+------------------+

| Host      | User | Password                                  | password_expired |

+-----------+------+-------------------------------------------+------------------+

| localhost | root | *A848DE7CCD839E924921BEE41711991DDA0D529E | Y                |

+-----------+------+-------------------------------------------+------------------+

1 row in set (0.00 sec)

mysql> update user set password=PASSWORD('p12#456')

    -> where user='root' and host='root' or host='localhost';

Query OK, 1 row affected (0.00 sec)

Rows matched: 1  Changed: 1  Warnings: 0

新設置用戶或更改密碼後需用flush privileges刷新MySQL的系統權限相關表，否則會出現拒絕訪問，還有一種方法，就是重新啟動mysql服務器，來使新設置生效。

mysql> flush privileges;

Query OK, 0 rows affected (0.00 sec)

mysql> quit

Bye

[root@DB-Server init.d]# /etc/rc.d/init.d/mysql restart

Shutting down MySQL..140722 15:02:27 mysqld_safe mysqld from pid file /var/lib/mysql/DB-Server.pid ended

[  OK  ]

Starting MySQL.[  OK  ]

[2]-  Done                    mysqld_safe --user=mysql --skip-grant-tables --skip-networking

[root@DB-Server init.d]# mysql -u root p

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

[root@DB-Server init.d]# mysql -u root -p

Enter password: 

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 2

Server version: 5.6.19

Copyright (c) 2000, 2014, 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.

mysql> 

至此問題解決，但是還有不少地方有些疑惑，為啥出現這個錯誤？ 其實這麼多資料都只是說了解決方法，但是都回避了問題的原因。

參考資料：

http://huangyifa163.blog.163.com/blog/static/262875752011127102215790/

http://sundful.iteye.com/blog/704337

http://wenku.baidu.com/view/735ffa41be1e650e52ea995a.html

http://www.cnblogs.com/sunson/articles/2172086.html

http://blog.163.com/eric1945@126/blog/static/164934572201081494343373/

http://www.cnblogs.com/likai198981/archive/2013/04/06/3002518.html

mysql ERROR 1045 (28000): Access denied for user

你還是改密碼吧，這個提示真是密碼不對。
hi.baidu.com/...198b74 這個是忘記root密碼修改密碼的方法
 

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

是不是mysql服務器停啦..