mysql语句查询用户权限过程详解

在MySQL中，如何查看一个用户被授予了那些权限呢？ 授予用户的权限可能分全局层级权限、数据库层级权限、表层级别权限、列层级别权限、子程序层级权限。具体分类如下：

全局层级

全局权限适用于一个给定服务器中的所有数据库。这些权限存储在mysql.user表中。GRANT ALL ON *.*和REVOKE ALL ON *.*只授予和撤销全局权限。

数据库层级

数据库权限适用于一个给定数据库中的所有目标。这些权限存储在mysql.db和mysql.host表中。GRANT ALL ON db_name.*和REVOKE ALL ON db_name.*只授予和撤销数据库权限。

表层级

表权限适用于一个给定表中的所有列。这些权限存储在mysql.tables_priv表中。GRANT ALL ON db_name.tbl_name和REVOKE ALL ON db_name.tbl_name只授予和撤销表权限。

列层级

列权限适用于一个给定表中的单一列。这些权限存储在mysql.columns_priv表中。当使用REVOKE时，您必须指定与被授权列相同的列。

子程序层级

CREATE ROUTINE, ALTER ROUTINE, EXECUTE和GRANT权限适用于已存储的子程序。这些权限可以被授予为全局层级和数据库层级。而且，除了CREATE ROUTINE外，这些权限可以被授予为子程序层级，并存储在mysql.procs_priv表中。

1：那么我们来创建一个测试账号test，授予全局层级的权限。如下所示：

mysql> grant select,insert on *.* to test@'%' identified by 'test';
Query OK, 0 rows affected (0.01 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> 

那么可以用下面两种方式查询授予test的权限。如下所示：

mysql> show grants for test;
+--------------------------------------------------------------------------------------------------------------+
| Grants for test@% |
+--------------------------------------------------------------------------------------------------------------+
| GRANT SELECT, INSERT ON *.* TO 'test'@'%' IDENTIFIED BY PASSWORD '*94BDCEBE19083CE2A1F959FD02F964C7AF4CFC29' |
+--------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> select * from mysql.user where user='test'\G;
*************************** 1. row ***************************
Host: %
User: test
Password: *94BDCEBE19083CE2A1F959FD02F964C7AF4CFC29
Select_priv: Y
Insert_priv: Y
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: 0
max_updates: 0
max_connections: 0
max_user_connections: 0
plugin: mysql_native_password
authentication_string: 
password_expired: N
1 row in set (0.04 sec)
ERROR: 
No query specified
mysql> 

2：那么我们来创建一个测试账号test，授予数据库层级的权限。如下所示：

mysql> drop user test;
Query OK, 0 rows affected (0.00 sec)
mysql> grant select,insert,update,delete on MyDB.* to test@'%' identified by 'test';
Query OK, 0 rows affected (0.01 sec)
mysql> 
mysql> select * from mysql.user where user='test'\G; --可以看到无任何授权。
mysql> select * from mysql.db where user='test'\G;
*************************** 1. row ***************************
Host: %
Db: MyDB
User: test
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
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
1 row in set (0.04 sec)
ERROR: 
No query specified
mysql> 
mysql> show grants for test;
+-----------------------------------------------------------------------------------------------------+
| Grants for test@% |
+-----------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'test'@'%' IDENTIFIED BY PASSWORD '*94BDCEBE19083CE2A1F959FD02F964C7AF4CFC29' |
| GRANT SELECT, INSERT, UPDATE, DELETE ON `MyDB`.* TO 'test'@'%' |
+-----------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
mysql> 

3：那么我们来创建一个测试账号test，授予表层级的权限。如下所示：

mysql> drop user test;
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> grant all on MyDB.kkk to test@'%' identified by 'test';
Query OK, 0 rows affected (0.01 sec)
mysql> 
mysql> show grants for test;
+-----------------------------------------------------------------------------------------------------+
| Grants for test@% |
+-----------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'test'@'%' IDENTIFIED BY PASSWORD '*94BDCEBE19083CE2A1F959FD02F964C7AF4CFC29' |
| GRANT ALL PRIVILEGES ON `MyDB`.`kkk` TO 'test'@'%' |
+-----------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
mysql> select * from mysql.tables_priv\G;
*************************** 1. row ***************************
Host: %
Db: MyDB
User: test
Table_name: kkk
Grantor: root@localhost
Timestamp: 0000-00-00 00:00:00
Table_priv: Select,Insert,Update,Delete,Create,Drop,References,Index,Alter,Create View,Show view,Trigger
Column_priv: 
1 row in set (0.01 sec)
ERROR: 
No query specified
mysql> 

4：那么我们来创建一个测试账号test，授予列层级的权限。如下所示：

mysql> drop user test;
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> grant select (id, col1) on MyDB.TEST1 to test@'%' identified by 'test';
Query OK, 0 rows affected (0.01 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> 
mysql> select * from mysql.columns_priv;
+------+------+------+------------+-------------+---------------------+-------------+
| Host | Db | User | Table_name | Column_name | Timestamp | Column_priv |
+------+------+------+------------+-------------+---------------------+-------------+
| % | MyDB | test | TEST1 | id | 0000-00-00 00:00:00 | Select |
| % | MyDB | test | TEST1 | col1 | 0000-00-00 00:00:00 | Select |
+------+------+------+------------+-------------+---------------------+-------------+
2 rows in set (0.00 sec)
mysql> show grants for test;
+-----------------------------------------------------------------------------------------------------+
| Grants for test@% |
+-----------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'test'@'%' IDENTIFIED BY PASSWORD '*94BDCEBE19083CE2A1F959FD02F964C7AF4CFC29' |
| GRANT SELECT (id, col1) ON `MyDB`.`TEST1` TO 'test'@'%' |
+-----------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
mysql> 

5：那么我们来创建一个测试账号test，授子程序层级的权限。如下所示：

mysql> DROP PROCEDURE IF EXISTS PRC_TEST;
Query OK, 0 rows affected (0.00 sec)
mysql> DELIMITER //
mysql> CREATE PROCEDURE PRC_TEST()
-> BEGIN
-> SELECT * FROM kkk;
-> END //
Query OK, 0 rows affected (0.00 sec)
mysql> DELIMITER ;
mysql> grant execute on procedure MyDB.PRC_TEST to test@'%' identified by 'test';
Query OK, 0 rows affected (0.01 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> 
mysql> show grants for test;
+-----------------------------------------------------------------------------------------------------+
| Grants for test@% |
+-----------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'test'@'%' IDENTIFIED BY PASSWORD '*94BDCEBE19083CE2A1F959FD02F964C7AF4CFC29' |
| GRANT EXECUTE ON PROCEDURE `MyDB`.`prc_test` TO 'test'@'%' |
+-----------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
mysql> select * from mysql.procs_priv where User='test';
+------+------+------+--------------+--------------+----------------+-----------+---------------------+
| Host | Db | User | Routine_name | Routine_type | Grantor | Proc_priv | Timestamp |
+------+------+------+--------------+--------------+----------------+-----------+---------------------+
| % | MyDB | test | PRC_TEST | PROCEDURE | root@localhost | Execute | 0000-00-00 00:00:00 |
+------+------+------+--------------+--------------+----------------+-----------+---------------------+
1 row in set (0.00 sec)
mysql> 

所以，如果需要查看用户被授予的权限，就需要从这五个层级来查看被授予的权限。从上到下或从小到上，逐一检查各个层级被授予的权限。

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