I understand how to create a new user with privileges, but what is the correct way to change privileges for users that are already created?

We are running a DB audit and some of the users have way more access then is needed. Plus I don't know the passwords for most of these MySQL users, so I don't want to delete them and create new ones.

3 Answers 3


To list users:

select user,host from mysql.user;

To show privileges:

show grants for 'user'@'host';

To change privileges, first revoke. Such as:

revoke all privileges on *.* from 'user'@'host';

Then grant the appropriate privileges as desired:

grant SELECT,INSERT,UPDATE,DELETE ON `db`.* TO 'user'@'host';

Finally, flush:

flush privileges;

The MySQL documentation is excellent:

  • 3
    Well without revoke, it will be dublicates privileges;
    – Sergey
    Sep 27, 2012 at 12:38
  • 12
    mysql documentation is near unreadable, this answer is much better Mar 1, 2016 at 10:02
  • I think (revoke all privileges on . from 'user'@'host'; ) should be (revoke all on . from 'user'@'host';) Thanks,
    – Nicholas
    Jul 12, 2018 at 14:42
  • 2
    this answer is plain wrong "flush privileges" does not apply to privileges set with grant. the above process results in the user having no privilege at all between the moment the revoke and the grant queries are run, and additionally flushing the grants cache for no reason __ this would work if you perform regular queries against the mysql.user table rather than using grants and if the server does not crash or stop between the queries. Aug 16, 2018 at 9:48
  • How can it be done without leaving the user with no privileges during the gap?
    – Jimbali
    Feb 10, 2022 at 10:30

without downtime you can do this (example for granting ALTER command):

UPDATE mysql.db
set Alter_priv='Y'

for any other privilege, see current user privileges and right columns to change:

FROM mysql.db

My solution was to use ansible mysql_user module. It maintains the user permissions without revoking everything.
Grant a few permissions in test db on testtable table:
playbook.yaml content:

- name:
  hosts: localhost
    ansible_python_interpreter: /usr/bin/python3
  - name: Test user
      name: testuser
      password: testpassword
        'test.testtable': SELECT,INSERT,ALTER
      login_user: root
      login_password: root
      state: present

Run ansible-playbook playbook.yaml
Then revoke ALTER by removing from priv:

'test.testtable': SELECT,INSERT

run again ansible-playbook playbook.yaml
I checked mysql logs to make sure it does not revoke all, before grant:

2022-10-10T14:34:54.911222Z      1632 Query     SHOW GRANTS FOR 'testuser'@'localhost'
2022-10-10T14:34:54.911797Z      1632 Query     REVOKE ALTER ON `test`.`testtable` FROM 'testuser'@'localhost'
2022-10-10T14:34:54.947049Z      1632 Query     FLUSH PRIVILEGES
2022-10-10T14:34:54.951583Z      1632 Query     SHOW GRANTS FOR 'testuser'@'localhost'

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