用户权限管理

一，权限范围：

1，全局

grant all on *.* to 'qn'@'%'

2，数据库

grant all on test.* to 'qn'@'%'

3，表

grant all on test.q to 'qn'@'%'

4，列

grant select(q) on test.q to 'qn'@'%'

二，比较特别权限type :

all : 指所有权限

USAGE : 没权限匿名

三，特殊库Test:

By default, the mysql.db table contains rows that permit access by any user to the test database and other databases with names that start with test_. (These rows have an empty User column value, which for access-checking purposes matches any user name.) This means that such databases can be used even by accounts that otherwise possess no privileges. If you want to remove any-user access to test databases, do so as follows:

默认，mysql.db记录了允许对test库或者以test_开头库的访问的用户。有写记录USER列值是空，匹配任何用户作为访问检查的目的。这意味着这库能被用户使用，没有权限的。如果你想移除任何用户对test库的访问。做如下的

shell> mysql -u root -p

Enter password: (enter root password here)

mysql> DELETE FROM mysql.db WHERE Db LIKE 'test%';

mysql> FLUSH PRIVILEGES;

FLUSH语句促使服务重读grant表。否则，权限更改保留未被服务器通知，除非你重启

更改之后，只有有全局数据库权限或明确授权的用户才能访问test库

所以不要用test库做权限的测试