1.通过mysql数据库的user表查看用户相关信息

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> select host,user,password from user;
+-----------+------+-------------------------------------------+
| host      | user | password                                  |
+-----------+------+-------------------------------------------+
| localhost | root | *87F2746835A04895BB77E12AA5054A767******* |
| qxyw      | root |                                           |
| 127.0.0.1 | root |                                           |
| localhost |      |                                           |
| qxyw      |      |                                           |
+-----------+------+-------------------------------------------+
5 rows in set (0.00 sec)

2.创建数据库

mysql> create database [databasename] default character set utf8 collate utf8_general_ci;
Query OK, 1 row affected (0.00 sec)

3.创建用户

mysql> create user 'dba'@'%' identified by '*******';
Query OK, 0 rows affected (0.00 sec)

user表中host列的值的意义

%               匹配所有主机

localhost    localhost不会被解析成IP地址，直接通过UNIXsocket连接

127.0.0.1   会通过TCP/IP协议连接，并且只能在本机访问；

::1              ::1就是兼容支持ipv6的，表示同ipv4的127.0.0.1

4.对dba用户给予针对指定数据库进行增删改查的权限

mysql> grant select,insert,update,delete,create on [databasename].* to dba;
Query OK, 0 rows affected (0.00 sec)

注意：修改完权限以后 一定要刷新服务，或者重启服务，刷新服务用：FLUSH PRIVILEGES

5.可以通过show grants命令查看权限，若想要在原来的基础上增加权限则继续执行grant

mysql> grant drop on [databasename].* to dba;
Query OK, 0 rows affected (0.00 sec)
mysql> show grants for dba;
+----------------------------------------------------------------------------------------------------+
| Grants for dba@%                                                                                   |
+----------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'dba'@'%' IDENTIFIED BY PASSWORD '*****************************************' |
| GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP ON `[databasename]`.* TO 'dba'@'%'              |
+----------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)

6.通过revoke命令可以移除用户的相关权限

mysql> revoke drop on [databasename].* from dba;
Query OK, 0 rows affected (0.00 sec)
mysql> show grants for dba;
+----------------------------------------------------------------------------------------------------+
| Grants for dba@%                                                                                   |
+----------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'dba'@'%' IDENTIFIED BY PASSWORD '*****************************************' |
| GRANT SELECT, INSERT, UPDATE, DELETE, CREATE ON `[databasename]`.* TO 'dba'@'%'                    |
+----------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)