本文基于MySQL8.0，记录一下完整的远程访问的过程，以及这个过程中可能遇到的问题，MySQL运行在阿里云服务器，CentOS 7.6 64位
顺便说下，买服务器还是要双十二这种拉新活动再买，用一个新的支付宝账号购买，能便宜一大半，不然双核4G就两千多块了。
这里默认防火墙已经向外暴露3306端口/关闭防火墙了，以及阿里云安全组配置暴露3306端口，在Windows通过Navicat测试连接
随便创建一个用户：
mysql> create user 'dev'@'localhost' identified by 'huluhulu'; //创建用户dev，只能在localhost使用，密码huluhulu Query OK, 0 rows affected (0.00 sec) mysql> select host, user ,authentication_string, plugin from user; //查看user，host，加密后的字符串，以及加密类型 +-----------+------------------+------------------------------------------------------------------------+-----------------------+ | host | user | authentication_string | plugin | +-----------+------------------+------------------------------------------------------------------------+-----------------------+ | % | root | *43C685FF9E03403DD721CF54B4E40B199DA06624 | mysql_native_password | | % | test | *43C685FF9E03403DD721CF54B4E40B199DA06624 | mysql_native_password | | localhost | dev | $A$005$6dH-H a.'^JNmbBkSYomGJK2180WHglWpm4mw.BIJGtuPX0qcBrOLIcMqC | caching_sha2_password | | localhost | mysql.infoschema | $A$005$THISISACOMBINATIONOFINVALIDSALTANDPASSWORDTHATMUSTNEVERBRBEUSED | caching_sha2_password | | localhost | mysql.session | $A$005$THISISACOMBINATIONOFINVALIDSALTANDPASSWORDTHATMUSTNEVERBRBEUSED | caching_sha2_password | | localhost | mysql.sys | $A$005$THISISACOMBINATIONOFINVALIDSALTANDPASSWORDTHATMUSTNEVERBRBEUSED | caching_sha2_password | | localhost | root | *43C685FF9E03403DD721CF54B4E40B199DA06624 | mysql_native_password | +-----------+------------------+------------------------------------------------------------------------+-----------------------+ 7 rows in set (0.00 sec)
创建用户之后，默认加密类型为caching_sha2_password
Navicat登录结果：
修改用户加密方式：
mysql> alter user 'dev'@'localhost'identified with mysql_native_password by 'huluhulu'; Query OK, 0 rows affected (0.00 sec) mysql> select host, user ,authentication_string, plugin from user; +-----------+------------------+------------------------------------------------------------------------+-----------------------+ | host | user | authentication_string | plugin | +-----------+------------------+------------------------------------------------------------------------+-----------------------+ | % | root | *43C685FF9E03403DD721CF54B4E40B199DA06624 | mysql_native_password | | % | test | *43C685FF9E03403DD721CF54B4E40B199DA06624 | mysql_native_password | | localhost | dev | *43C685FF9E03403DD721CF54B4E40B199DA06624 | mysql_native_password | | localhost | mysql.infoschema | $A$005$THISISACOMBINATIONOFINVALIDSALTANDPASSWORDTHATMUSTNEVERBRBEUSED | caching_sha2_password | | localhost | mysql.session | $A$005$THISISACOMBINATIONOFINVALIDSALTANDPASSWORDTHATMUSTNEVERBRBEUSED | caching_sha2_password | | localhost | mysql.sys | $A$005$THISISACOMBINATIONOFINVALIDSALTANDPASSWORDTHATMUSTNEVERBRBEUSED | caching_sha2_password | | localhost | root | *43C685FF9E03403DD721CF54B4E40B199DA06624 | mysql_native_password | +-----------+------------------+------------------------------------------------------------------------+-----------------------+ 7 rows in set (0.00 sec)
因为可视化工具只支持旧的加密方式mysql_native_password，如果是caching_sha2_password是无法远程连接登录的
Navicat登录结果：
因为dev用户支持的是localhost登录，我们需要把他修改为远程访问机器的IP或者%，%代表任意地址
修改用户登录授权地址：
mysql> rename user 'dev'@'localhost' to 'dev'@'%'; Query OK, 0 rows affected (0.00 sec)
Navicat登录结果：
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到这里我们实现访问登录，但是登录dev用户，我们发现只有一个数据库
查看dev用户权限：
mysql> show grants for 'dev'@'%'; +---------------------------------+ | Grants for dev@% | +---------------------------------+ | GRANT USAGE ON *.* TO `dev`@`%` | +---------------------------------+ 1 row in set (0.00 sec)
dev用户的权限为USAGE，MySQL用户权限介绍如下：
-- 权限列表 ALL [PRIVILEGES] -- 设置除GRANT OPTION之外的所有简单权限 ALTER -- 允许使用ALTER TABLE ALTER ROUTINE -- 更改或取消已存储的子程序 CREATE -- 允许使用CREATE TABLE CREATE ROUTINE -- 创建已存储的子程序 CREATE TEMPORARY TABLES -- 允许使用CREATE TEMPORARY TABLE CREATE USER -- 允许使用CREATE USER, DROP USER, RENAME USER和REVOKE ALL PRIVILEGES。 CREATE VIEW -- 允许使用CREATE VIEW DELETE -- 允许使用DELETE DROP -- 允许使用DROP TABLE EXECUTE -- 允许用户运行已存储的子程序 FILE -- 允许使用SELECT...INTO OUTFILE和LOAD DATA INFILE INDEX -- 允许使用CREATE INDEX和DROP INDEX INSERT -- 允许使用INSERT LOCK TABLES -- 允许对您拥有SELECT权限的表使用LOCK TABLES PROCESS -- 允许使用SHOW FULL PROCESSLIST REFERENCES -- 未被实施 RELOAD -- 允许使用FLUSH REPLICATION CLIENT -- 允许用户询问从属服务器或主服务器的地址 REPLICATION SLAVE -- 用于复制型从属服务器（从主服务器中读取二进制日志事件） SELECT -- 允许使用SELECT SHOW DATABASES -- 显示所有数据库 SHOW VIEW -- 允许使用SHOW CREATE VIEW SHUTDOWN -- 允许使用mysqladmin shutdown SUPER -- 允许使用CHANGE MASTER, KILL, PURGE MASTER LOGS和SET GLOBAL语句，mysqladmin debug命令；允许您连接（一次），即使已达到max_connections。 UPDATE -- 允许使用UPDATE USAGE -- “无权限”的同义词 GRANT OPTION -- 允许授予权限
USAGE就是无权限，我们现在给dev用户添加select权限，但是只针对数据库mysql的test表，查看权限
mysql> grant select on mysql.test to 'dev'@'%' with grant option; Query OK, 0 rows affected (0.01 sec) mysql> show grants for 'dev'@'%'; +---------------------------------------------------------------+ | Grants for dev@% | +---------------------------------------------------------------+ | GRANT USAGE ON *.* TO `dev`@`%` | | GRANT SELECT ON `mysql`.`test` TO `dev`@`%` WITH GRANT OPTION | +---------------------------------------------------------------+ 2 rows in set (0.00 sec)
Navicat登录结果：只显示一张表
修改用户加密方式：执行select语句是可以的，
SELECT * FROM test;
但是如果执行delete，或者其他DML以及DDL语句，是没有权限的
[SQL]DELETE FROM test WHERE Id=100; [Err] 1142 - DELETE command denied to user 'dev'@'202.101.0.2' for table 'test'
后序为了测试方便，把权限赋予所有的数据库的所有表，以及添加update，select权限
mysql> grant select,update, delete on *.* to 'dev'@'%' with grant option; Query OK, 0 rows affected (0.00 sec) mysql> show grants for 'dev'@'%'; +--------------------------------------------------------------------+ | Grants for dev@% | +--------------------------------------------------------------------+ | GRANT SELECT, insert, UPDATE, DELETE ON *.* TO `dev`@`%` WITH GRANT OPTION | | GRANT SELECT ON `mysql`.`test` TO `dev`@`%` WITH GRANT OPTION | +--------------------------------------------------------------------+ 2 rows in set (0.00 sec)
撤销dev用户delete权限：
mysql> revoke delete on *.* from 'dev'@'%'; Query OK, 0 rows affected (0.01 sec) mysql> show grants for 'dev'@'%'; +---------------------------------------------------------------------------+ | Grants for dev@% | +---------------------------------------------------------------------------+ | GRANT SELECT, INSERT, UPDATE, ALTER ON *.* TO `dev`@`%` WITH GRANT OPTION | | GRANT SELECT ON `mysql`.`test` TO `dev`@`%` WITH GRANT OPTION | +---------------------------------------------------------------------------+ 2 rows in set (0.00 sec)
撤销dev用户所有权限：
mysql> revoke all privileges on *.* from 'dev'@'%'; Query OK, 0 rows affected (0.01 sec) mysql> flush privileges; Query OK, 0 rows affected (0.00 sec)
PS：flush privileges命令只刷新你MySQL所在机器的权限，如果远程访问，你需要在远程操作所在的机器使用flush privileges进行
刷新权限，或者断开连接，并重新连接也会刷新
到此为止，关于一般用户权限控制的操作讲完了，包括远程访问可能遇到的问题，算是一个入门吧，希望对新手有所帮助。