[imooc@localhost ~]$ mysql -uroot -p -h******
Enter password:
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Your MySQL connection id is 8
Server version: 8.0.16 MySQL Community Server - GPL

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mysql> use mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show grants;
±-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Grants for root@% |
±-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, RELOAD, SHUTDOWN, PROCESS, FILE, REFERENCES, INDEX, ALTER, SHOW DATABASES, SUPER, CREATE TEMPORARY TABLES, LOCK TABLES, EXECUTE, REPLICATION SLAVE, REPLICATION CLIENT, CREATE VIEW, SHOW VIEW, CREATE ROUTINE, ALTER ROUTINE, CREATE USER, EVENT, TRIGGER, CREATE TABLESPACE, CREATE ROLE, DROP ROLE ON . TO root@% WITH GRANT OPTION |
±-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> create user ‘imooc’@’%’ identified by ‘132456’;
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
mysql> set global validate_password=0;
ERROR 1193 (HY000): Unknown system variable 'validate_password’
mysql> set global validate_password.policy=0;
Query OK, 0 rows affected (0.00 sec)

mysql> set global validate_password.length=1;
Query OK, 0 rows affected (0.00 sec)

mysql> create user ‘imooc’@’%’ identified by ‘132456’;
ERROR 1396 (HY000): Operation CREATE USER failed for ‘imooc’@’%‘
mysql> drop user ‘imooc’@’%’;
Query OK, 0 rows affected (0.07 sec)

mysql> create user ‘imooc’@’%’ identified by ‘132456’;
Query OK, 0 rows affected (0.11 sec)

mysql> ALTER USER ‘root’@’%’ IDENTIFIED BY ‘password’ PASSWORD EXPIRE NEVER;
Query OK, 0 rows affected (0.07 sec)

mysql> ALTER USER ‘root’@’%’ IDENTIFIED WITH mysql_native_password BY ‘lq_mysql2019CN’;
Query OK, 0 rows affected (0.01 sec)

mysql> flush privileges
-> ;
Query OK, 0 rows affected (0.01 sec)

mysql> ALTER USER ‘imooc’@’%’ IDENTIFIED BY ‘password’ PASSWORD EXPIRE NEVER;
Query OK, 0 rows affected (0.08 sec)

mysql> ALTER USER ‘imooc’@’%’ IDENTIFIED WITH mysql_native_password BY ‘123456’;
Query OK, 0 rows affected (0.01 sec)

mysql> flush privileges
-> ;
Query OK, 0 rows affected (0.01 sec)

mysql> grant all privileges on . to ‘imooc’@’%’;
Query OK, 0 rows affected (0.11 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)

mysql> revoke all privileges on . from ‘imooc’@’%’;
ERROR 1227 (42000): Access denied; you need (at least one of) the SYSTEM_USER privilege(s) for this operation
mysql> revoke all privileges on . from imooc;
ERROR 1227 (42000): Access denied; you need (at least one of) the SYSTEM_USER privilege(s) for this operation