ERROR 1044 (42000): Access denied for user ‘root‘@‘localhost‘

从供应商那边接手一个MySQL数据库（数据库版本为5.7.21 MySQL Community Server (GPL)），在创建账号时遇到了“ERROR 1044 (42000): Access denied for user ‘root‘@‘localhost‘ to database xxx”错误，如下所示

mysql> grant all on xxx.* to [email protected]‘192.168.%‘ identified by ‘xxx‘;

ERROR 1044 (42000): Access denied for user ‘root‘@‘localhost‘ to database ‘xxxx‘

mysql> 

照理说，root用户应该有任何权限，那么为什么出现这个错误呢？ 查看当前用户为[email protected]，顺便查看了一下各个root账号的权限。如下所示：

mysql> select current_user() from dual;

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

| current_user() |

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

| [email protected] |

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

1 row in set (0.00 sec

mysql> select host,user from user where user=‘root‘;

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

| host      | user     |

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

| %         | root     |

| 127.0.0.1 | root     |

| ::1       | root     |

| localhost | root     |

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

7 rows in set (0.00 sec)

mysql>  show grants for [email protected]‘localhost‘;

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

| Grants for [email protected]                                    |

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

| GRANT ALL PRIVILEGES ON *.* TO ‘root‘@‘localhost‘            |

| GRANT PROXY ON ‘‘@‘‘ TO ‘root‘@‘localhost‘ WITH GRANT OPTION |

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

2 rows in set (0.00 sec)

mysql> show grants for [email protected]‘127.0.0.1‘;

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

| Grants for [email protected]                                           |

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

| GRANT ALL PRIVILEGES ON *.* TO ‘root‘@‘127.0.0.1‘ WITH GRANT OPTION |

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

1 row in set (0.00 sec)

mysql> show grants for [email protected]‘%‘;

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

| Grants for [email protected]%                         |

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

| GRANT ALL PRIVILEGES ON *.* TO ‘root‘@‘%‘ |

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

1 row in set (0.00 sec)

如上所示，[email protected]账号没有WITH GRANT OPTION选项，关于WITH GRANT OPTION选项，如果想让授权的用户，也可以将这些权限授予给其他用户，需要选项 “WITH GRANT OPTION“ 。说就是将权限传递给第三方。这也是上面[email protected]用户给其它用后授权报错的原因，如果以 [email protected]登录（此账号拥有WITHGRANT OPTION选项），创建用户并授权就不会有这个错误：

# mysql -host 127.0.0.1 -u root -p

Enter password: 

mysql>  grant all on eqmobilewarehouse.* to [email protected]‘192.168.%‘ identified by ‘test1249‘;

Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> flush privileges;

Query OK, 0 rows affected (0.00 sec)

当然还有其它方面的原因也会引起这个错误，不过在这个案例当中，确实仅仅是因为上面原因引起。特此记录一下这个案例@！

原文地址：https://www.cnblogs.com/kerrycode/p/9198566.html