SHOW GRANTS FOR root@invalid_host; ERROR 42000: There is no such grant defined for user 'root' on host 'invalid_host' create user test; create user foo; create role foo; grant foo to test; set role foo; show grants for test; Grants for test@% GRANT foo TO 'test'@'%' GRANT USAGE ON *.* TO 'test'@'%' show grants for foo; Grants for foo GRANT USAGE ON *.* TO 'foo' show grants for foo@'%'; ERROR 42000: Access denied for user 'test'@'%' to database 'mysql' drop user test, foo; drop role foo; CREATE TABLE t1 (a INT); LOCK TABLE t1 WRITE; REVOKE EXECUTE ON PROCEDURE sp FROM u; ERROR HY000: Table 'user' was not locked with LOCK TABLES REVOKE PROCESS ON *.* FROM u; ERROR HY000: Table 'user' was not locked with LOCK TABLES DROP TABLE t1; create database mysqltest1; use mysqltest1; create table t1(id int); insert t1 values(2); create user u1@localhost; grant select on mysqltest1.t1 to u1@localhost; grant update on mysqltest1.* to u1@localhost; update mysqltest1.t1 set id=1 where id=2; drop user u1@localhost; drop database mysqltest1;