MySQL Grant Create and All Privileges on User’s Own Database

Do not mess with the mysql db. There is a lot more going on there than just the users table. Your best bet is the "SHOW GRANTS FOR" command. I have a lot of CLI maintenance aliases and functions in my .bashrc (actually my .bash_aliases that I source in my .bashrc). This function:

mygrants()
{
  mysql -B -N $@ -e "SELECT DISTINCT CONCAT(
    'SHOW GRANTS FOR \'', user, '\'@\'', host, '\';'
    ) AS query FROM mysql.user" | \
  mysql $@ | \
  sed 's/\(GRANT .*\)/\1;/;s/^\(Grants for .*\)/## \1 ##/;/##/{x;p;x;}'
}

The first mysql command uses SQL to generate valid SQL which is piped to the second mysql command. The output is then piped through sed to add pretty comments.

The $@ in the command will allow you to call it as: mygrants --host=prod-db1 --user=admin --password=secret

You can use your full unix tool kit on this like so:

mygrants --host=prod-db1 --user=admin --password=secret | grep rails_admin | mysql --host=staging-db1 --user=admin --password=secret

That is THE right way to move users. Your MySQL ACL is modified with pure SQL.

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:

https://dev.mysql.com/doc/refman/8.0/en/access-control.html