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

從供應商那邊接手一個MySQL數據庫（數據庫版本為5.7.21 MySQL Community Server (GPL)），在創建賬號時遇到了“ERROR 1044 (42000): Access denied for user 'root'@'localhost' to database xxx”錯誤，如下所示

 

 

mysql> grant all on xxx.* to xxx@'192.168.%' identified by 'xxx';
ERROR 1044 (42000): Access denied for user 'root'@'localhost' to database 'xxxx'
mysql>

 

照理說，root用戶應該有任何權限，那么為什么出現這個錯誤呢？ 查看當前用戶為root@localhost，順便查看了一下各個root賬號的權限。如下所示：

 

 

mysql> select current_user() from dual;
+----------------+
| current_user() |
+----------------+
| root@localhost |
+----------------+
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 root@'localhost';
+--------------------------------------------------------------+
| Grants for root@localhost                                    |
+--------------------------------------------------------------+
| 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 root@'127.0.0.1';
+---------------------------------------------------------------------+
| Grants for root@127.0.0.1                                           |
+---------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'127.0.0.1' WITH GRANT OPTION |
+---------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> show grants for root@'%';
+-------------------------------------------+
| Grants for root@%                         |
+-------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' |
+-------------------------------------------+
1 row in set (0.00 sec)

 

 

 

    如上所示，root@localhost賬號沒有WITH GRANT OPTION選項，關於WITH GRANT OPTION選項，如果想讓授權的用戶，也可以將這些權限授予給其他用戶，需要選項 “WITH GRANT OPTION“ 。也就是說有這個選項就可以將權限傳遞給第三方。這也是上面root@localhost用戶給其它用后授權報錯的原因，如果以 root@127.0.0.1登錄（此賬號擁有WITHGRANT OPTION選項），創建用戶並授權就不會有這個錯誤，如下所示：

 

 

# mysql -host 127.0.0.1 -u root -p
Enter password:




mysql>  grant all on xxx.* to xxx@'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)

 

當然還有其它方面的原因也可能會引起這個錯誤，不過在這個案例當中，確實僅僅是因為上面原因引起。特此記錄一下這個案例@！