Get a list of Site Administrators
The following SQL will help you see which users are site admins in a MySQL/MariaDB database using the find_in_set function to query the values listed in the mdl_config siteadmins key-value.
select u.*
from mdl_user u
where
find_in_set(u.id, (select value from mdl_config where name = 'siteadmins'))
Note you need to use find_in_set instead of the in operator which doesn’t handle the commas returned to separate each siteadmin’s user ID.