To view MySQL user permissions, use the SHOW GRANTS command, with the syntax SHOW GRANTS FOR 'username'@'hostname'; For example, SHOW GRANTS FOR 'test_user'@'localhost'; You can view the local connection user permissions; if you are not sure of the host name, you can use the % wildcard instead. In the execution results, USAGE means there is no actual permissions, SELECT, INSERT, etc. are common operation permissions, and the content after ON indicates the scope of the permissions, such as mydb.* means all objects under the mydb database. This command is suitable for troubleshooting permission problems, permission migration and copying, and avoiding misdeletion of permissions. Notes include: It is necessary to accurately match the user name and host name. USAGE does not mean that there is no permission at all. After modifying the permission, you may need to manually refresh the permission table. Mastering this command can effectively manage MySQL user permissions.
The SHOW GRANTS
command in MySQL is an important tool for viewing user permissions, especially when debugging permission issues or doing security audits. If you want to know what permissions a user has, you can see it at a glance by using this command directly.

How to view user permissions
To view the permissions of a user, the basic syntax is:
SHOW GRANTS FOR 'Username'@'Hostname';
For example, if you want to see the permissions of user test_user
to connect locally, you can execute:

SHOW GRANTS FOR 'test_user'@'localhost';
Note that the username and hostname here must exactly match the records in the MySQL permissions system. If you are not sure about the hostname part, you can use %
wildcard instead, such as 'test_user'@'%'
to indicate a connection on any host.
How to read permission information
After executing the command, you will see results similar to the following:

GRANT USAGE ON *.* TO 'test_user'@'localhost' GRANT SELECT, INSERT ON `mydb`.* TO 'test_user'@'localhost' GRANT EXECUTE ON PROCEDURE `mydb`.`myproc` TO 'test_user'@'localhost'
Each line represents a class of permissions:
- USAGE says that it does not have any actual permissions, but the account exists.
- SELECT, INSERT are common database operation permissions.
- The content after ON represents the scope of permissions, such as
mydb.*
represents all tables under the mydb database. - If you have permissions to stored procedures, functions, or events, it will also be listed.
Some permissions may only be targeted at a specific table or column, and the content needs to be carefully checked.
Use scenarios and precautions
- Troubleshooting permission issues : When the application error "No permission to access a table", use this command to quickly confirm whether the corresponding permissions are really granted.
- Permission migration/copy : You can copy
GRANT
statements from one user's authorization statement and execute them in another environment to achieve the purpose of permission synchronization. - Avoid mistaken deletion permissions : Sometimes we may use
REVOKE
to revoke permissions, but it is best to see what permissions are currently available to avoid revoking them.
Common misunderstandings:
- I only remember the user name and forgot the host name, resulting in the lack of permissions being found.
- When I see
USAGE
, I think there is no permission. In fact, it may be that the permission at a certain database level has been missed. - Forgot to refresh the permissions. If
FLUSH PRIVILEGES
is not executed after modifying the permissions, you may see old data (although it will be automatically refreshed most of the time).
Basically that's it. Master the SHOW GRANTS
command and cooperate with a little permission knowledge, you can easily manage MySQL user permissions.
The above is the detailed content of mysql show grants for user. For more information, please follow other related articles on the PHP Chinese website!

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