Can't create a new user with all privileges on AWS RDS MySQL instance

I've initiated a AWS RDS MySQL instance and would like to create an additional user, who has all privileges on all databases;

grant all privileges on *.* to "someuser"@"10.0.0.0/255.255.0.0";
ERROR 1045 (28000): Access denied for user 'root'@'%' (using password: YES)

As you can see, I'm not allowed to do so, even though I'm triggering the command as root.

How can I solve this?

Solution 1:

It is not allowed in RDS to grant all permissions to *.*, but you can use a trick:

GRANT ALL PRIVILEGES ON `%`.* TO 'someuser'@XXX;

Also, don't forget: ALL [PRIVILEGES] gives all permissions except GRANT OPTION and PROXY!

When using RDS (Managed DB service) you simply can't create a root user as you're trying to do.

Simply use

CREATE USER 'username'@'%' IDENTIFIED BY 'userpassword';
GRANT SELECT ON [your_database].[some_table] TO 'username'@'%';