When MySQL resets the root password and modifies the password, an error occurs. The password field does not exist

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One .MySQL Reset root password

close MySQL The server ：

service mysql stop

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Entry directory ,

cd /usr/local/mysql/bin  

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 Start in safe mode  MySQL

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./mysqld_safe --skip-grant-tables &

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Be careful ： Maybe your system doesn't safe_mysqld Program (Windows or Ubuntu operating system ) , have access to mysqld： mysqld --skip-grant-tables &

After starting , root User logs in with blank password mysql：

# mysql -u root

mysql> update mysql.user set password=PASSWORD('123456') where User='root';   #  Change Password 
mysql> flush privileges;  #  Refresh the permissions 
mysql> quit 

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start-up MySQL：

service mysql start

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Two .MySQL5.7 Appears when the password is changed ERROR 1054 (42S22): Unknown column ‘password’ in ‘field list’

Error reported after execution 　ERROR 1054(42S22) Unknown column ‘password’ in ‘field list’

The reason for the mistake is 5.7 Version mysql There is no password This field ,password Field changed to authentication_string

So please use the command ：

 update mysql.user set authentication_string=PASSWORD('root') where User='root';

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thus , modify root The password succeeded .

3、 ... and . An error occurs when creating a user , operation failed : Because this user currently exists , Or you do not have refresh permission after deleting users .

ERROR 1396 (HY000): Operation CREATE USER failed for 'code'@'localhost'

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Four .MySQL Creating users and authorizations

(1) Create user

command :

CREATE USER 'username'@'host' IDENTIFIED BY 'password';

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explain ：

• username： The user name you will create
• host： Specifies on which host the user can log in , If available to local users localhost, If you want the user to be able to Login from any remote host , You can use wildcards %
• password： The login password of the user , The password can be null , If it is empty, the user can log in to the server without a password

Example ：

CREATE USER 'dog'@'localhost' IDENTIFIED BY '123456';
CREATE USER 'pig'@'192.168.1.101_' IDENDIFIED BY '123456';
CREATE USER 'pig'@'%' IDENTIFIED BY '123456';
CREATE USER 'pig'@'%' IDENTIFIED BY '';
CREATE USER 'pig'@'%';

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(2) to grant authorization :

command :

GRANT privileges ON databasename.tablename TO 'username'@'host'

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explain :

• privileges： User action permissions , Such as SELECT,INSERT,UPDATE etc. , Use if you want to grant permissions ALL
• databasename： Database name
• tablename： Table name , Available if you want to grant the user access to all databases and tables * Express , Such as *.*

Example :

GRANT SELECT, INSERT ON test.user TO 'pig'@'%';
GRANT ALL ON *.* TO 'pig'@'%';

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Be careful :

Users authorized by the above command cannot authorize other users , If you want the user to be authorized , Use the following command :

GRANT privileges ON databasename.tablename TO 'username'@'host' WITH GRANT OPTION;

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(3). Set and change user passwords

command :

SET PASSWORD FOR 'username'@'host' = PASSWORD('newpassword');

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If it is the current login user :

SET PASSWORD = PASSWORD("newpassword");

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Example :

SET PASSWORD FOR 'pig'@'%' = PASSWORD("123456");

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(4). Revoke user privileges

command :

REVOKE privilege ON databasename.tablename FROM 'username'@'host';

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explain :

privilege, databasename, tablename： Same authorization part

Example :

REVOKE SELECT ON *.* FROM 'pig'@'%';

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Be careful :

Let's say you're giving it to the user 'pig'@'%' That's what happens when you delegate （ Or similar ）：GRANT SELECT ON test.user TO 'pig'@'%', In the use REVOKE SELECT ON *.* FROM 'pig'@'%'; The command does not undo the user pair test In the database user Tabular SELECT operation . contrary , If authorized to use is GRANT SELECT ON *.* TO 'pig'@'%'; be REVOKE SELECT ON test.user FROM 'pig'@'%'; The command also cannot undo the user pair test In the database user Tabular Select jurisdiction .

Specific information can be ordered SHOW GRANTS FOR 'pig'@'%'; see .

(5). Delete user

command :

DROP USER 'username'@'host';

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Reference resources ：https://www.jianshu.com/p/d7b9c468f20d

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