mysql权限管理：
mysql的权限控制，首先在user表判断有没有权限连，连上后看有没有全局权限。然后看db表有哪些库级别的权限。然后看tables_priv表有哪些表级别的权限。最后还可以看有哪些列级别的权限。
mysql权限检查：1.有没有权连接上来2.有没有权执行操作(crud)
服务器是如何判断用户有没有权限连接上来：1.你从哪里来，host2.你是谁，user
3.你的密码
用户的这3个信息存储在mysql数据库的user表下
mysql> usemysql
mysql> desc user;
mysql> select Host,User from user;+-----------+---------------+
| Host | User |
+-----------+---------------+
| localhost | mysql.session |mysql.session用户必须从localhost连接| localhost | mysql.sys |mysql.sys用户必须从localhost连接| localhost | root |root用户必须从localhost连接+-----------+---------------+
就算知道用户名和密码，但是可以限制ip。
修改user的host域，update user set host="192.168.1.101" where user='root';
flushprivileges; 冲刷权限，
如何修改用户的密码：update user set password=passwiord('111111') where user='root'flushprivileges;
mysql库下有一个db表，
用户连上来先通过user表，看能不能进来，然后经过db表判断有没有某个库的操作权，然后通过tables_priv判断有没有库下哪个表的权限。//新增一个用户，grant[权限1，权限2，权限3......] on 哪个库.哪个表 to 用户@'host' identified by 'password'常用权限all(所有权限)，creat,drop,insert,delete,update,selectmysql> grant all on *.* to lisi@'127.0.0.1' identified by '111111';
Query OK,0rows affected
mysql> select Host,User from user;+-----------+---------------+
| Host | User |
+-----------+---------------+
| 127.0.0.1 | lisi |
| localhost | mysql.session |
| localhost | mysql.sys |
| localhost | root |
+-----------+---------------+
C:\Users\Administrator>mysql -h127.0.0.1 -ulisi -p //用户lisi登陆
Enter password:******Welcometo the MySQL monitor. Commands end with ; or\g.
Your MySQL connection idis 8Server version:5.7.20MySQL Community Server (GPL)
mysql> select * from user where user='lisi'\G;*************************** 1. row ***************************Host:127.0.0.1
User: lisi
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
Create_priv: Y
Drop_priv: Y
Reload_priv: Y
Shutdown_priv: Y
Process_priv: Y
File_priv: Y
Grant_priv: N
References_priv: Y
Index_priv: Y
Alter_priv: Y
Show_db_priv: Y
Super_priv: Y
Create_tmp_table_priv: Y
Lock_tables_priv: Y
Execute_priv: Y
Repl_slave_priv: Y
Repl_client_priv: Y
Create_view_priv: Y
Show_view_priv: Y
Create_routine_priv: Y
Alter_routine_priv: Y
Create_user_priv: Y
Event_priv: Y
Trigger_priv: Y
Create_tablespace_priv: Y
ssl_type:
ssl_cipher:
x509_issuer:
x509_subject:
max_questions:0max_updates:0max_connections:0max_user_connections:0plugin: mysql_native_password
authentication_string:*FD571203974BA9AFE270FE62151AE967ECA5E0AA
password_expired: N
password_last_changed:2017-12-29 21:30:25password_lifetime:NULLaccount_locked: N1 row in set (0.00sec)//收回权限，revoke all on *.* from lisi@'127.0.0.1',
mysql> revoke all on *.* from lisi@'127.0.0.1';
Query OK,0rows affected
mysql> select * from user where user='lisi'\G;*************************** 1. row ***************************Host:127.0.0.1
User: lisi
Select_priv: N
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Reload_priv: N
Shutdown_priv: N
Process_priv: N
File_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Show_db_priv: N
Super_priv: N
Create_tmp_table_priv: N
Lock_tables_priv: N
Execute_priv: N
Repl_slave_priv: N
Repl_client_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: N
Alter_routine_priv: N
Create_user_priv: N
Event_priv: N
Trigger_priv: N
Create_tablespace_priv: N
ssl_type:
ssl_cipher:
x509_issuer:
x509_subject:
max_questions:0max_updates:0max_connections:0max_user_connections:0plugin: mysql_native_password
authentication_string:*FD571203974BA9AFE270FE62151AE967ECA5E0AA
password_expired: N
password_last_changed:2017-12-29 21:30:25password_lifetime:NULLaccount_locked: N1 row in set (0.00sec)
mysql库下面的user里面可以检测能不能登陆，并且里面的权限是全局的，所有库所有表的。//不是全局授权，而是分库分表管理权限。grant all on test3.* to lidi@'127.0.0.1'; //给lisi test3库所有表的所有权限。//针对某个表做授权grant creat,drop,insert,update,select on test3.goods to lisi@'127.0.0.1';//test3库的goods表做权限控制，//数据库级别的权限在db表中，表级别的权限在tables_priv表中。
mysql> select * from db \G; //哪个用户在哪个库哪个主机有哪些权限*************************** 1. row ***************************Host: localhost
Db: performance_schemaUser: mysql.session
Select_priv: Y
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Create_tmp_table_priv: N
Lock_tables_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: N
Alter_routine_priv: N
Execute_priv: N
Event_priv: N
Trigger_priv: N*************************** 2. row ***************************Host: localhost
Db: sysUser: mysql.sys
Select_priv: N
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Create_tmp_table_priv: N
Lock_tables_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: N
Alter_routine_priv: N
Execute_priv: N
Event_priv: N
Trigger_priv: Y*************************** 4. row ***************************Host:127.0.0.1Db: test2User: lisi
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
Create_priv: Y
Drop_priv: Y
Grant_priv: N
References_priv: Y
Index_priv: Y
Alter_priv: Y
Create_tmp_table_priv: Y
Lock_tables_priv: Y
Create_view_priv: Y
Show_view_priv: Y
Create_routine_priv: Y
Alter_routine_priv: Y
Execute_priv: Y
Event_priv: Y
Trigger_priv: Y4 rows in set (0.00sec)
mysql> select * fromtables_priv \G;*************************** 1. row ***************************Host: localhost
Db: mysqlUser: mysql.session
Table_name:userGrantor: boot@connectinghostTimestamp: 0000-00-00 00:00:00Table_priv:SelectColumn_priv:*************************** 2. row ***************************Host: localhost
Db: sysUser: mysql.sys
Table_name: sys_config
Grantor: root@localhost
Timestamp: 2017-12-25 15:09:21Table_priv:SelectColumn_priv:*************************** 3. row ***************************Host:127.0.0.1Db: test3User: lisi
Table_name: goods
Grantor: root@localhost
Timestamp: 0000-00-00 00:00:00Table_priv:Select,Insert,Update,Create,DropColumn_priv:3 rows in set (0.00sec)//mysql的权限控制可以精确到列，常用的授权项，
函数释放结果集)
