? MySQL REVOKE Permissions

? Quick Overview

The REVOKE statement in MySQL is used to remove previously granted privileges from a user. It helps database administrators control access and maintain security by restricting what actions a user can perform.

? Key Concepts

Permissions are removed using the REVOKE command
Privileges can be revoked at global, database, table, or column level
Changes take effect immediately after execution
Usually combined with GRANT for access control

? Syntax / Theory

The basic syntax of the REVOKE command removes one or more privileges from a specific user and host.

? View Code Example

-- General syntax to revoke privileges in MySQL
REVOKE privilege_name
ON database_name.table_name
FROM 'username'@'host';

? Code Example(s)

The following example revokes the INSERT and UPDATE permissions from a user on a specific database table.

? View Code Example

-- Revoke INSERT and UPDATE permissions from user 'app_user'
REVOKE INSERT, UPDATE
ON company_db.employees
FROM 'app_user'@'localhost';

? Live Output / Explanation

What Happens?

After executing the above command:

The user app_user can no longer insert or update rows
Other permissions like SELECT remain unchanged
No server restart is required

✅ Tips & Best Practices

Always check current privileges using SHOW GRANTS
Revoke only necessary permissions to follow least privilege principle
Be specific with database and table names
Use FLUSH PRIVILEGES only when modifying system tables manually

? Try It Yourself

Practice revoking permissions safely:

? View Code Example

-- Check existing permissions for a user
SHOW GRANTS FOR 'test_user'@'localhost';

-- Revoke SELECT permission from a database
REVOKE SELECT
ON sample_db.*
FROM 'test_user'@'localhost';

After running the commands, try querying the database as test_user to observe the permission change.