How can I get a list of user accounts using the command line in MySQL?

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How to List MySQL User Accounts from the Command Line

A command-line interface showing MySQL commands and output, with a database icon in the background.

Learn various command-line methods to retrieve a list of user accounts and their associated privileges in MySQL, essential for database administration and security audits.

Managing user accounts is a fundamental task for any MySQL database administrator. Whether you're performing a security audit, debugging access issues, or simply getting an overview of who has access to your database, knowing how to list user accounts from the command line is crucial. This article will guide you through several methods to achieve this, covering different levels of detail and privilege information.

Understanding MySQL User Accounts

In MySQL, user accounts are defined by a combination of a username and a host from which they can connect. For example, 'myuser'@'localhost' is a different user than 'myuser'@'%'. The '%' wildcard signifies that the user can connect from any host. This host-specific definition is a key aspect of MySQL's security model, allowing granular control over network access.

erDiagram
    USER ||--o{ HOST : "can connect from"
    USER { 
        VARCHAR(255) user_name PK
        VARCHAR(255) host_name PK
        VARCHAR(255) authentication_string
    }
    HOST { 
        VARCHAR(255) host_name PK
        VARCHAR(255) description
    }

Simplified ER Diagram of MySQL User and Host Relationship

Method 1: Querying the mysql.user Table

The most direct way to list user accounts is by querying the user table within the mysql system database. This table stores all user account information, including usernames, hosts, and authentication details. You'll need appropriate privileges (e.g., SELECT on the mysql.user table) to perform this query.

SELECT user, host FROM mysql.user;

Basic query to list all users and their allowed hosts.

This command provides a straightforward list of user and host combinations. If you need more details, such as authentication plugins or password expiration information, you can select additional columns from the mysql.user table.

SELECT user, host, authentication_string, plugin, password_expired FROM mysql.user;

Query to retrieve detailed user information including authentication method.

Method 2: Using SELECT User, Host FROM mysql.db for Database-Specific Access

While mysql.user shows all defined users, the mysql.db table provides insight into which users have privileges on specific databases. This can be useful for understanding database-level access control.

SELECT User, Host, Db FROM mysql.db;

Listing users with privileges on specific databases.

Method 3: Listing Users with SHOW GRANTS

The SHOW GRANTS statement is invaluable for understanding the specific privileges granted to a user. While it doesn't list all users directly, you can iterate through the users obtained from mysql.user to see their individual grants. This provides the most comprehensive view of a user's permissions.

SHOW GRANTS FOR 'myuser'@'localhost';
-- Replace 'myuser'@'localhost' with the actual user and host.

Example of showing grants for a specific user.

1. Connect to MySQL

Open your terminal and connect to your MySQL server using the mysql client:

mysql -u root -p

Enter your root password when prompted.

2. Select the mysql database

Once connected, switch to the mysql database:

USE mysql;

3. List users and hosts

Execute the query to retrieve user and host information:

SELECT user, host FROM user;

This will display a table of all user accounts defined on your MySQL server.