1.进入mysql命令行，输入root及密码
[root@localhost ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 19
Server version: 5.7.22 MySQL Community Server (GPL)
Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
2.用户管理及权限设置
// 管理用户
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
//查询用户
mysql> select host,user from user;
+-----------+---------------+
| host | user |
+-----------+---------------+
| % | root |
| % | test |
| localhost | mysql.session |
| localhost | mysql.sys |
| localhost | root |
+-----------+---------------+
5 rows in set (0.00 sec)
//创建用户（用户：admin，密码:123456）
mysql> create user admin identified by '123456';
Query OK, 0 rows affected (0.00 sec)
// 删除用户admin
mysql> drop user admin;
Query OK, 0 rows affected (0.00 sec)
// 重新创建用户（用户：admins，密码:123456）
mysql> create user admins identified by '123456';
Query OK, 0 rows affected (0.00 sec)
mysql> select host, user from user;
+-----------+---------------+
| host | user |
+-----------+---------------+
| % | admins |
| % | root |
| % | test |
| localhost | mysql.session |
| localhost | mysql.sys |
| localhost | root |
+-----------+---------------+
6 rows in set (0.00 sec)
// 查看用户admins的权限
mysql> show grants for admins;
+------------------------------------+
| Grants for admins@% |
+------------------------------------+
| GRANT USAGE ON *.* TO 'admins'@'%' |
+------------------------------------+
1 row in set (0.00 sec)
// 赋予权限（给用户admins，授予数据库test的查询权限）
mysql> grant select on test.* to admins;
Query OK, 0 rows affected (0.00 sec)
// 查看用户admins的权限
mysql> show grants for admins;
+------------------------------------------+
| Grants for admins@% |
+------------------------------------------+
| GRANT USAGE ON *.* TO 'admins'@'%' |
| GRANT SELECT ON `test`.* TO 'admins'@'%' |
+------------------------------------------+
2 rows in set (0.00 sec)
// 收回权限（对用户admins，收回数据库test的查询权限）
mysql> revoke select on test.* from admins;
Query OK, 0 rows affected (0.01 sec)
// 查看用户admins的权限
mysql> show grants for admins;
+------------------------------------+
| Grants for admins@% |
+------------------------------------+
| GRANT USAGE ON *.* TO 'admins'@'%' |
+------------------------------------+
1 row in set (0.00 sec)
// 赋予权限（给用户admins，授予数据库test的查询、更新、删除、插入等权限）
mysql> grant select, update, delete, insert on test.* to admins;
Query OK, 0 rows affected (0.00 sec)
// 查看用户admins的权限
mysql> show grants for admins;
+------------------------------------------------------------------+
| Grants for admins@% |
+------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'admins'@'%' |
| GRANT SELECT, INSERT, UPDATE, DELETE ON `test`.* TO 'admins'@'%' |
+------------------------------------------------------------------+
2 rows in set (0.01 sec)
// 赋予权限（给用户admins，授予数据库test的新建表、删除表或删除数据库等权限）
mysql> grant create,drop on test.* to admins;
Query OK, 0 rows affected (0.00 sec)
// 查看用户admins的权限
mysql> show grants for admins;
+--------------------------------------------------------------------------------+
| Grants for admins@% |
+--------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'admins'@'%' |
| GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP ON `test`.* TO 'admins'@'%' |
+--------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
// 刷新权限（使设置的权限生效）
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
// 查看root的权限
mysql> show grants for root;
+-------------------------------------------+
| Grants for root@% |
+-------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' |
+-------------------------------------------+
1 row in set (0.00 sec)
以下是用户可以享受的常见可能权限的简短列表。
ALL PRIVILEGES - 正如我们前面所看到的，这将允许MySQL用户访问指定的数据库（或者如果系统中没有选择数据库）
CREATE-允许他们创建新的表或数据库
DROP-允许他们删除表或数据库
DELETE-允许他们从表中删除行
INSERT-允许它们向表中插入行
SELECT-允许他们使用Select命令来读取数据库
UPDATE-允许他们更新表行
GRANT OPTION - 允许他们授予或删除其他用户的权限
要向特定用户提供权限，可以使用此框架：
GRANT [type of permission] ON [database name].[table name] TO ‘[username]’@'localhost’;
如果要向其授予对任何数据库或任何表的访问权限，请确保在数据库名称或表名称的地方放置星号（*）。
每次更新或更改权限时，请务必使用Flush Privileges命令。
如果您需要撤消权限，则结构与授予的结构几乎相同：
REVOKE [type of permission] ON [database name].[table name] FROM ‘[username]’@‘localhost’;
正如您可以使用DROP删除数据库一样，您可以使用DROP完全删除用户：
DROP USER ‘demo’@‘localhost’;
要测试您的新用户，请通过键入注销
quit
并使用此命令在终端中重新登录：
mysql -u [username]-p