Centos下MySql用户管理

1.建立用户

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

 

2.用户受权

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

说明: privileges - 用户的操做权限,如SELECT , INSERT , UPDATE 等(详细列表见该文最后面).若是要授予所的权限则使用ALL.;databasename - 数据库名,tablename-表名,若是要授予该用户对全部数据库和表的相应操做权限则可用*表示, 如*.*.

例子:

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

注意:用以上命令受权的用户不能给其它用户受权,若是想让该用户能够受权,用如下命令:

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

 

3.取消受权

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

说明: privilege, databasename, tablename - 同受权部分.

例子:

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

注意: 假如你在给用户'pig'@'%'受权的时候是这样的(或相似的):GRANT SELECT ON test.user TO 'pig'@'%', 则在使用REVOKE SELECT ON *.* FROM 'pig'@'%';命令并不能撤销该用户对test数据库中user表的SELECT 操做.相反,若是受权使用的是GRANT SELECT ON *.* TO 'pig'@'%';则REVOKE SELECT ON test.user FROM 'pig'@'%';命令也不能撤销该用户对test数据库中user表的Select 权限.

具体信息能够用命令 SHOW GRANTS FOR 'pig'@'%';  查看.

 

4.设置或修改密码

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

若是是当前登录用户用 SET PASSWORD = PASSWORD("newpassword");

例子:

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

若是忘记root密码，操做以下：

1).linux切换到root用户

2).修改MySql的登录设置，编辑my.cnf文件

　　 [root@promote /]# vi /etc/my.cnf 

　　在[mysqld]字段下加入一句： skip-grant-tables

　　保存退出。

3).从新启动mysqld

　　 [root@promote /]# service mysqld restart 

4).以后能够免密码进入MySql，而后use mysql

[root@promote /]# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.18 MySQL Community Server (GPL)

Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> use mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed

5).修改root用户密码

mysql> update mysql.user set authentication_string=password('root') where User='root' and Host='localhost';
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 1

6).退出MySql，编辑my.cnf，删除skip-grant-tables一行

7).可用root用户的新密码登进MySql

 

5.删除用户

DROP USER 'username'@'host'; 

 

 

 

附表：在MySql中的操做权限

 

ALTER	Allows use of ALTER TABLE.
ALTER ROUTINE	Alters or drops stored routines.
CREATE	Allows use of CREATE TABLE.
CREATE ROUTINE	Creates stored routines.
CREATE TEMPORARY TABLE	Allows use of CREATE TEMPORARY TABLE.
CREATE USER	Allows use of CREATE USER, DROP USER, RENAME USER, and REVOKE ALL PRIVILEGES.
CREATE VIEW	Allows use of CREATE VIEW.
DELETE	Allows use of DELETE.
DROP	Allows use of DROP TABLE.
EXECUTE	Allows the user to run stored routines.
FILE	Allows use of SELECT... INTO OUTFILE and LOAD DATA INFILE.
INDEX	Allows use of CREATE INDEX and DROP INDEX.
INSERT	Allows use of INSERT.
LOCK TABLES	Allows use of LOCK TABLES on tables for which the user also has SELECT privileges.
PROCESS	Allows use of SHOW FULL PROCESSLIST.
RELOAD	Allows use of FLUSH.
REPLICATION	Allows the user to ask where slave or master
CLIENT	servers are.
REPLICATION SLAVE	Needed for replication slaves.
SELECT	Allows use of SELECT.
SHOW DATABASES	Allows use of SHOW DATABASES.
SHOW VIEW	Allows use of SHOW CREATE VIEW.
SHUTDOWN	Allows use of mysqladmin shutdown.
SUPER	Allows use of CHANGE MASTER, KILL, PURGE MASTER LOGS, and SET GLOBAL SQL statements. Allows mysqladmin debug command. Allows one extra connection to be made if maximum connections are reached.
UPDATE	Allows use of UPDATE.
USAGE	Allows connection without any specific privileges.