Normally, creating a second (or third, fourth…) MySQL superuser who has all available database privileges is as simple as executing:
GRANT ALL PRIVILEGES ON *.* TO 'newuser'@'%' IDENTIFIED BY 'password';
However, MySQL database in Amazon RDS and Amazon Aurora only allow one superuser to exist; however, you can neatly replicate the effect of having a superuser (the same full set of privileges) by modifying your SQL query to the following:
GRANT EXECUTE, PROCESS, SELECT, SHOW DATABASES, SHOW VIEW, ALTER, ALTER ROUTINE, CREATE, CREATE ROUTINE, DELETE, CREATE VIEW, INDEX, EVENT, DROP, TRIGGER, REFERENCES, INSERT, CREATE USER, UPDATE, RELOAD, LOCK TABLES, REPLICATION SLAVE, REPLICATION CLIENT, CREATE TEMPORARY TABLES ON *.* TO 'newuser'@'%' WITH GRANT OPTION;
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