MySQL增加/删除用户、授权、修改密码
// 创建用户
mysql> use mysql;
mysql> insert into user(Host,User,Password) values('localhost','yongfu_a',password('my_password'));
// 刷新系统权限表
mysql> flush privileges;
//退出后登录一下
mysql>exit;
说明：
至此创建mysql的第二个用户：yongfu_a（第一个用户是root），他的密码是my_password。需要刷新系统权限表flush privilege，该用户才能生效登录。此时该用户（yongfu_a）仅有在本机（localhost）使用密码（my_password）登录的权 限，还没有其他权限，需要使用GRANT命令对该用户进行相应授权。
通过GRANT授权的方式新增用户
// 以root用户登录mysql
[yongfu]$ mysql -uroot -p
// 新增一个新用户yongfu_b
mysql> grant all privileges on *.* to yongfu_b@'192.168.1.%' identified by 'my_password_2';
说明：
至此创建了mysql的第三个用户：yongfu_b，他的密码是my_password_2。不需要使用flush privilege刷新系统权限表，改用户立即生效。此时该用户（yongfu_b）可以在192.168.1.0/24的网段上的任意机器使用密码 （my_password_2）登录。同时已经对所有库的所有表赋予了全部权限
ps:使用grant方法新增用户更方便也更省事。只需要一步就可以完成新增用户和用户授权的全部操作
2. MySQL修改用户密码
2.1 直接修改数据库修改密码
// 在数据库中修改密码字段
mysql> use mysql
mysql> update user set Password = password("new_password") where User = "yongfu_a" and Host="localhost";
mysql> flush privileges;
2.2 通过GRANT方法修改密码
// 其实就是新增用户那个方法，grant本身是授权、授予的意思。
// 修改用户yongfu_b的密码为 my_password_new
mysql> grant all privileges on *.* to yongfu_b@'192.168.1.%' identified by 'my_password_new';
3. 授权和取消权限
3.1 授权mysql使用GRANT命令对用户进行授权。前面我们已经数次接触到GRANT命令，用它添加了一个用户，也为用户修改了密码，同时为yongfu_a用户授予了SUPER权限。其实GRANT设计的目的本身只是为了授权的。
// 首先我们查看 yongfu_a 用户有哪些权限
mysql> select * from user where User='yongfu_a' /G;
*************************** 1. row ***************************
Host: localhost
User: yongfu_a
Password: *1603BD6A73604A872220561294D3C5916A7B1E60
Select_priv: N
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
省略后面的
**************************************************************************************************************
// 从上面可以看出，yongfu_a 用户只有前面授权的SUPER权限。
// 怎么给yongfu_a用户授予增删改查的权限？使用如下命令：
mysql> GRANT SELECT,UPDATE,INSERT,DELETE on *.* to yongfu_a@'localhost';// 再查看下权限情况：
mysql> select * from user where User='yongfu_a' /G;*************************** 1. row ***************************
Host: localhost
User: yongfu_a
Password: *1603BD6A73604A872220561294D3C5916A7B1E60
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
********************************************************
// 这时已经被授予了增删改查的权限了，同时发现SUPER权限还是保留的。
3.2 取消授权// REVOKE语句的语法格式如下：
// 其中privileges是要取消的权限，user是要被取消权限的用户名， 特别注意user前的关键字变为了from。
REVOKE privileges (columns) on what from user ;
// 取消 yongfu_a用户的增删改查权限
mysql> REVOKE SELECT,UPDATE,INSERT,DELETE on *.* from yongfu_a@'localhost';
mysql> select * from user where User='yongfu_a' /G;
就可以看到，被取消了增删改查的权限了
REVOKE语句用于取消用户的权限，而不可以删除用户。
4. 删除用户取消了所有的权限，用户仍然可以连接到服务器。要想彻底的删除用户，必须使用DELETE语句将该用户的记录从mysql数据库中的user表中删除。
// 使用DELETE删除用户yongfu_a，代码如下：
mysql> use mysql
Database changed
mysql> delete from user where user='yongfu_a' and host='localhost' ;
mysql>flush privileges ;
Query OK, 1 row affected (0.02 sec)
其中，delete用于删除用户，flush告诉服务器重新加载授权表。
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
MySQL: An Introduction to the World's Most Popular Database
Apr 12, 2025 am 12:18 AM
MySQL is an open source relational database management system, mainly used to store and retrieve data quickly and reliably. Its working principle includes client requests, query resolution, execution of queries and return results. Examples of usage include creating tables, inserting and querying data, and advanced features such as JOIN operations. Common errors involve SQL syntax, data types, and permissions, and optimization suggestions include the use of indexes, optimized queries, and partitioning of tables.
How to connect to the database of apache
Apr 13, 2025 pm 01:03 PM
Apache connects to a database requires the following steps: Install the database driver. Configure the web.xml file to create a connection pool. Create a JDBC data source and specify the connection settings. Use the JDBC API to access the database from Java code, including getting connections, creating statements, binding parameters, executing queries or updates, and processing results.
MySQL's Place: Databases and Programming
Apr 13, 2025 am 12:18 AM
MySQL's position in databases and programming is very important. It is an open source relational database management system that is widely used in various application scenarios. 1) MySQL provides efficient data storage, organization and retrieval functions, supporting Web, mobile and enterprise-level systems. 2) It uses a client-server architecture, supports multiple storage engines and index optimization. 3) Basic usages include creating tables and inserting data, and advanced usages involve multi-table JOINs and complex queries. 4) Frequently asked questions such as SQL syntax errors and performance issues can be debugged through the EXPLAIN command and slow query log. 5) Performance optimization methods include rational use of indexes, optimized query and use of caches. Best practices include using transactions and PreparedStatemen
Why Use MySQL? Benefits and Advantages
Apr 12, 2025 am 12:17 AM
MySQL is chosen for its performance, reliability, ease of use, and community support. 1.MySQL provides efficient data storage and retrieval functions, supporting multiple data types and advanced query operations. 2. Adopt client-server architecture and multiple storage engines to support transaction and query optimization. 3. Easy to use, supports a variety of operating systems and programming languages. 4. Have strong community support and provide rich resources and solutions.
MySQL's Role: Databases in Web Applications
Apr 17, 2025 am 12:23 AM
The main role of MySQL in web applications is to store and manage data. 1.MySQL efficiently processes user information, product catalogs, transaction records and other data. 2. Through SQL query, developers can extract information from the database to generate dynamic content. 3.MySQL works based on the client-server model to ensure acceptable query speed.
How to start mysql by docker
Apr 15, 2025 pm 12:09 PM
The process of starting MySQL in Docker consists of the following steps: Pull the MySQL image to create and start the container, set the root user password, and map the port verification connection Create the database and the user grants all permissions to the database
Laravel Introduction Example
Apr 18, 2025 pm 12:45 PM
Laravel is a PHP framework for easy building of web applications. It provides a range of powerful features including: Installation: Install the Laravel CLI globally with Composer and create applications in the project directory. Routing: Define the relationship between the URL and the handler in routes/web.php. View: Create a view in resources/views to render the application's interface. Database Integration: Provides out-of-the-box integration with databases such as MySQL and uses migration to create and modify tables. Model and Controller: The model represents the database entity and the controller processes HTTP requests.
How to install mysql in centos7
Apr 14, 2025 pm 08:30 PM
The key to installing MySQL elegantly is to add the official MySQL repository. The specific steps are as follows: Download the MySQL official GPG key to prevent phishing attacks. Add MySQL repository file: rpm -Uvh https://dev.mysql.com/get/mysql80-community-release-el7-3.noarch.rpm Update yum repository cache: yum update installation MySQL: yum install mysql-server startup MySQL service: systemctl start mysqld set up booting
