ERROR: Access denied for user 'root'@'localhost' (using password: NO)
发现：
mysql -u root@localhost -p 成功
mysql -u root -p 失败
mysql> SELECT user, host FROM mysql.user;
ERROR 1142 (42000): SELECT command denied to user ''@'localhost' for table 'user'
mysql> SELECT USER(), CURRENT_USER();
+--------------------------+----------------+
| USER() | CURRENT_USER() |
+--------------------------+----------------+
| root@localhost@localhost | @localhost |
+--------------------------+----------------+
1 row in set (0.01 sec)
原因: root 设置了密码，需要把root的密码清掉。
以下可以解决问题(方案一)：
1) service mysqld stop
2) mysqld_safe --user=mysql --skip-grant-tables --skip-networking &
3) mysql -u root
4) Setup new MySQL root user password
use mysql;
select user,host,password from mysql.user;
+------+-----------+-------------------------------------------+
| user | host | password |
+------+-----------+-------------------------------------------+
| root | localhost | *CF1E6A25C954B638A451D6|
| root | centos64 | |
| root | 127.0.0.1 | |
| | localhost | |
| | centos64 | |
+------+-----------+-------------------------------------------+
update mysql.user set password=PASSWORD("***********") where User='root';
select user,host,password from mysql.user;
+------+-----------+-------------------------------------------+
| user | host | password |
+------+-----------+-------------------------------------------+
| root | localhost | *CF1E6A25C954B638A451D6 |
| root | centos64 | *CF1E6A25C954B638A451D6|
| root | 127.0.0.1 | *CF1E6A25C954B638A451D6|
| | localhost | |
| | centos64 | |
+------+-----------+-------------------------------------------+
flush privileges;
quit
5) Stop MySQL Server: service mysqld stop
6) Start MySQL server and test it:
service mysqld start
mysql -u root -p
SELECT USER(),CURRENT_USER();
+----------------+----------------+
| USER() | CURRENT_USER() |
+----------------+----------------+
| root@localhost | root@localhost |
+----------------+----------------+
1 row in set (0.00 sec)
以下可以解决问题(方案二)：
先用方案一登录mysql，再把root的密码设置为空
use mysql;
update user set password=PASSWORD("****************") where User='root';
flush privileges;
quit
=========================
在授权的时候报错：
ERROR 1044 (42000): Access denied for user 'root'@'%' to database 'mdm'
首先这里是用root用户操作，所以对这个数据库的权限绝对是最高级的，但是如果是非root用户操作，就可能是权限的问题，需要root用户授权。
出现上面的报错，很可能，其实应该可以说基本上都是因为my.cnf 文件里面有skip-name-resolve参数，这个参数导致这不能解析hostname或其它方式的登录, 所以登录任何用户，匹配的时候不走root@'localhost',或者127.0.0.1或者：：1 ，而是 一个劲的走root@'%'.
再来查看一下每种方式下的root用户的具体权限：
mysql> select * from user\G;
我这里root有三种解析登录方式分别是：Host: bidevedw\_db、Host: ::1、Host: %
一般情况还有Host:127.0.0.1、Host:localhost我的里面把哪两种删了。
请注意 ！
注意上面每条记录的的红色字体部分Grant_priv: Y
这个表示，以这种方式解析登录的root用户，是否有grant权限，Y则表示有授权限给其他用户的权限，N表示没有。
这里恰好，就是我们要找的原因，因为我的/my.cnf文件里面有skip-name-resolve参数，所以root都是解析到@'%'方式登录，于是就没有grant_priv权限。
解决方法：
1、在不重启MySQL服务的情况下，只需要在登录的时候加上-h参数。
例如：(a). /usr/local/mysql/bin/mysql -uroot -p123456 -h::1
(b)./usr/local/mysql/bin/mysql -uroot -p123456 -h127.0.0.1
(c)./usr/local/mysql/bin/mysql -uroot -p123456 -hlocalhost
2、需要重启MySQL。把skip-name-resolve参数去掉 ---- 还没验证。不过我记得，如果去掉了，日志里面会有大量的警告信息。我是因为那些警告信息，才添加的这个参数。
=========================================
HTTP Status 500 - javax.servlet.ServletException: java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
grant all privileges on aldb.* to root@localhost;
grant select on aldb.* to nobody@localhost;
grant all privileges on aldb.* to root@112.112.112.112;
grant select on aldb.* to nobody@112.112.112.112;
grant all privileges on aldb.* to root@res.res.res.res;
grant select on aldb.* to nobody@res.res.res.res;
use mysql
update user set password=password('xxxxxxxxxx') where user='root';
flush privileges;
====================================================
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
-----------------------------
/etc/init.d/mysqld status
/etc/init.d/mysqld stop
mysqld_safe --user=mysql --skip-grant-tables --skip-networking &
需要使用Enter中断会话
mysql -u root -p -hlocalhost
mysql> use mysql;
select Host, User, Password from user where user='root' and host='root' or host='localhost';
+-----------+--------+----------+
| Host | User | Password |
+-----------+--------+----------+
| localhost | | |
| localhost | aimin | |
| localhost | nobody | |
| localhost | root | |
+-----------+--------+----------+
4 rows in set (0.00 sec)
update user set password=PASSWORD('XXXXXXXXXXXXXX') where user='root' and host='root' or host='localhost';
flush privileges;
quit
/etc/init.d/mysqld restart
mysql -u root -p -hlocalhost
----------------------------------------------
# service mysqld stop
# mysqld_safe --user=mysql --skip-grant-tables --skip-networking &
# mysql -u root -p -hlocalhost
mysql> UPDATE user SET Password=PASSWORD('xxxxxxxxxxxxxxxxxxxxx') where USER='root';
mysql> FLUSH PRIVILEGES;
mysql> quit
# service mysqld start
restart CentOS.
-------------------------------------
Access denied for user 'root'@'localhost' (using password: YES)
ERROR 1044 (42000): Access denied for user 'root'@'localhost' to database 'mysql'
SELECT host,user,password,Grant_priv,Super_priv FROM mysql.user;
UPDATE mysql.user SET Grant_priv='Y', Super_priv='Y' WHERE User='root';
FLUSH PRIVILEGES;
GRANT ALL ON *.* TO 'root'@'localhost';
GRANT ALL ON *.* TO 'root'@'127.0.0.1';
GRANT ALL ON *.* TO 'root'@'xyz.xyz.com.cn';
GRANT ALL ON *.* TO 'root'@'123.123.123.123'; FLUSH PRIVILEGES;quit
REF:
http://www.cnblogs.com/kerrycode/p/3861719.html