仅新建一个newuser用户 
方法一：

MariaDB [(none)]> create user newuser@localhost identified by '123456';
Query OK, 0 rows affected (0.22 sec) MariaDB [(none)]> select user from mysql.user; +---------+ | user | +---------+ | aa | | root | | root | | | | aa | | bb | | lcz | | my | | mytest | | newuser | | nome | | root | | | | root | +---------+ 14 rows in set (0.00 sec) MariaDB [(none)]> 

方法二：

MariaDB [(none)]> insert into mysql.user(user,host,password) values('ggo','localhost',password('1234')); Query OK, 1 row affected, 4 warnings (0.24 sec) MariaDB [(none)]> flush privileges; Query OK, 0 rows affected (0.25 sec) 

效果

[root@localhost ~]# mysql -uggo -p
Enter password:
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 4 Server version: 5.5.52-MariaDB MariaDB Server Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MariaDB [(none)]> 

新建一个my用户并且授权全部操作权限

MariaDB [(none)]> grant all privileges on *.* to my@localhost identified by '123456';
Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> select user from mysql.user; +--------+ | user | +--------+ | aa | | root | | root | | | | aa | | bb | | lcz | | my | | mytest | | nome | | root | | | | root | +--------+ 13 rows in set (0.14 sec) MariaDB [(none)]> 

查看用户权限

MariaDB [(none)]> show grants for my@localhost;
+--------------------------------------------------------------------------------------------------------------------+
| Grants for my@localhost                                                                                            |
+--------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'my'@'localhost' IDENTIFIED BY PASSWORD '*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9' |
+--------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)MariaDB [(none)]>

指定部分授权

 grant insert,update,delete,select on *.* to mytest@localhost;