MySQL 5.1 because the user with host localhost is empty and the password is empty, the local user cannot log on.

Do not say. Directly on the MySQL user data, the fourth column, the host is localhost, the user is empty, the password is empty.

result in the local login in addition to the root of the account, other accounts do not need a password to log in, and affect the host as% of users landing.

You only need to delete the corresponding line.

mysql> Delete from user where host= ' localhost ' and user= ';
Query OK, 1 row Affected (0.00 sec)

I tried this here. User is NULL, seemingly unsupported. cannot be deleted.

Sql> SELECT * from user \g;
1. Row ***************************
Host:localhost
User:root
Password: *698756c099abd932c2f76c4a69c24608e8460b75
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:y
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
2. Row ***************************
Host:localhost.localdomain
User:root
Password:
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:y
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
3. Row ***************************
host:127.0.0.1
User:root
Password:
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:y
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
4. Row ***************************
Host:localhost
User:
Password:
Select_priv:n
Insert_priv:n
Update_priv:n
Delete_priv:n
Create_priv:n
Drop_priv:n
Reload_priv:n
Shutdown_priv:n
Process_priv:n
File_priv:n
Grant_priv:n
References_priv:n
Index_priv:n
Alter_priv:n
Show_db_priv:n
Super_priv:n
Create_tmp_table_priv:n
Lock_tables_priv:n
Execute_priv:n
Repl_slave_priv:n
Repl_client_priv:n
Create_view_priv:n
Show_view_priv:n
Create_routine_priv:n
Alter_routine_priv:n
Create_user_priv:n
Event_priv:n
Trigger_priv:n
Ssl_type:
Ssl_cipher:
X509_issuer:
X509_subject:
max_questions:0
max_updates:0
max_connections:0
max_user_connections:0
5. Row ***************************
Host:localhost.localdomain
User:
Password:
Select_priv:n
Insert_priv:n
Update_priv:n
Delete_priv:n
Create_priv:n
Drop_priv:n
Reload_priv:n
Shutdown_priv:n
Process_priv:n
File_priv:n
Grant_priv:n
References_priv:n
Index_priv:n
Alter_priv:n
Show_db_priv:n
Super_priv:n
Create_tmp_table_priv:n
Lock_tables_priv:n
Execute_priv:n
Repl_slave_priv:n
Repl_client_priv:n
Create_view_priv:n
Show_view_priv:n
Create_routine_priv:n
Alter_routine_priv:n
Create_user_priv:n
Event_priv:n
Trigger_priv:n
Ssl_type:
Ssl_cipher:
X509_issuer:
X509_subject:
max_questions:0
max_updates:0
max_connections:0
max_user_connections:0
6. Row ***************************
Host:%
User:cacti
Password: *698756c099abd932c2f76c4a69c24608e8460b75
Select_priv:n
Insert_priv:n
Update_priv:n
Delete_priv:n
Create_priv:n
Drop_priv:n
Reload_priv:n
Shutdown_priv:n
Process_priv:n
File_priv:n
Grant_priv:n
References_priv:n
Index_priv:n
Alter_priv:n
Show_db_priv:n
Super_priv:n
Create_tmp_table_priv:n
Lock_tables_priv:n
Execute_priv:n
Repl_slave_priv:n
Repl_client_priv:n
Create_view_priv:n
Show_view_priv:n
Create_routine_priv:n
Alter_routine_priv:n
Create_user_priv:n
Event_priv:n
Trigger_priv:n
Ssl_type:
Ssl_cipher:
X509_issuer:
X509_subject:
max_questions:0
max_updates:0
max_connections:0
max_user_connections:0
6 rows in Set (0.00 sec)

ERROR:
No query specified

MySQL 5.1 because the user with host localhost is empty and the password is empty, the local user cannot log on.