正常解释
%代表任何客户机都可以连接
localhost代表只可以本机连接
一般情况能访问本地数据库的都是加了权限了，一般都是禁止别的机器访问本地的mysql端口的，如果允许也是要加上指定ip才可以访问，这样才能保证数据库不会被远程访问。
1 前言
操作MySQL的时候发现，有时只建了%的账号，可以通过localhost连接，有时候却不可以，网上搜索也找不到满意的答案，干脆手动测试一波
2 两种连接方法
这里说的两种连接方法指是执行mysql命令时，-h参数填的是localhost还是IP, 两种连接方式的区别如下
-h 参数为 localhost
当-h参数为localhost的时候，实际上是使用socket连接的（默认连接方式）, 实例如下
[mysql@mysql-test-83 ~]$ /usr/local/mysql57/bin/mysql -utest_user -p -hlocalhost
Enter password:
========= 省略 ===========
mysql> status
/usr/local/mysql57/bin/mysql Ver 14.14 Distrib 5.7.21, for linux-glibc2.12 (x86_64) using EditLine wrapper
Connection id: 9
Current database:
Current user: test_user@localhost
SSL: Not in use
Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server version: 5.7.21-log MySQL Community Server (GPL)
Protocol version: 10
Connection: Localhost via UNIX socket
从Current user可以看到用户是xx@localhost, 连接方式为Localhost via UNIX socket
-h 参数为 IP
当-h参数为IP的时候，实际上是使用TCP连接的, 实例如下
[mysql@mysql-test-83 ~]$ /usr/local/mysql57/bin/mysql -utest_user -p -h127.0.0.1
Enter password:
========= 省略 ===========
mysql> status
--------------
/usr/local/mysql57/bin/mysql Ver 14.14 Distrib 5.7.21, for linux-glibc2.12 (x86_64) using EditLine wrapper
Connection id: 11
Current database:
Current user: test_user@127.0.0.1
SSL: Cipher in use is DHE-RSA-AES256-SHA
Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server version: 5.7.21-log MySQL Community Server (GPL)
Protocol version: 10
Connection: 127.0.0.1 via TCP/IP
Server characterset: utf8
从Current user可以看到用户是xx@127.0.0.1, 连接方式为TCP/IP
3 不同版本的差别
测试方法就是看能不能连接，如果不想看测试过程可以拉到最后看结论
3.1 MySQL 8.0
创建用户
mysql> select version();
+-----------+
| version() |
+-----------+
| 8.0.11 |
+-----------+
1 row in set (0.00 sec)
mysql> create user test_user@'%' identified by 'test_user';
Query OK, 0 rows affected (0.07 sec)
使用 localhost 登录
[root@mysql-test-72 ~]# /usr/local/mysql80/bin/mysql -utest_user -p -hlocalhost
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 8.0.11 MySQL Community Server - GPL
========= 省略 ===========
mysql> status
--------------
/usr/local/mysql80/bin/mysql Ver 8.0.11 for linux-glibc2.12 on x86_64 (MySQL Community Server - GPL)
Connection id: 9
Current database:
Current user: test_user@localhost
SSL: Not in use
Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server version: 8.0.11 MySQL Community Server - GPL
Protocol version: 10
Connection: Localhost via UNIX socket
...
使用 IP 登录
[root@mysql-test-72 ~]# /usr/local/mysql80/bin/mysql -utest_user -p -h127.0.0.1
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.11 MySQL Community Server - GPL
========= 省略 ===========
mysql> status
--------------
/usr/local/mysql80/bin/mysql Ver 8.0.11 for linux-glibc2.12 on x86_64 (MySQL Community Server - GPL)
Connection id: 8
Current database:
Current user: test_user@127.0.0.1
SSL: Cipher in use is DHE-RSA-AES128-GCM-SHA256
Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server version: 8.0.11 MySQL Community Server - GPL
Protocol version: 10
Connection: 127.0.0.1 via TCP/IP
结果显示8.0版本的MySQL, % 包括localhost
3.2 MySQL 5.7
创建 % 用户
db83-3306>>create user test_user@'%' identified by 'test_user';
Query OK, 0 rows affected (0.00 sec)
使用 localhost 登录
[mysql@mysql-test-83 ~]$ /usr/local/mysql57/bin/mysql -utest_user -p -hlocalhost
========= 省略 ===========
mysql> status
/usr/local/mysql57/bin/mysql Ver 14.14 Distrib 5.7.21, for linux-glibc2.12 (x86_64) using EditLine wrapper
Connection id: 9
Current database:
Current user: test_user@localhost
SSL: Not in use
Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server version: 5.7.21-log MySQL Community Server (GPL)
Protocol version: 10
Connection: Localhost via UNIX socket
....
使用 IP 登录
[mysql@mysql-test-83 ~]$ /usr/local/mysql57/bin/mysql -utest_user -p -h127.0.0.1
Enter password:
========= 省略 ===========
mysql> status
--------------
/usr/local/mysql57/bin/mysql Ver 14.14 Distrib 5.7.21, for linux-glibc2.12 (x86_64) using EditLine wrapper
Connection id: 11
Current database:
Current user: test_user@127.0.0.1
SSL: Cipher in use is DHE-RSA-AES256-SHA
Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server version: 5.7.21-log MySQL Community Server (GPL)
Protocol version: 10
Connection: 127.0.0.1 via TCP/IP
Server characterset: utf8
...
结果显示5.7版本的MySQL, % 包括localhost
3.3 MySQL 5.6
创建用户
db83-3306>>select version();
+------------+
| version() |
+------------+
| 5.6.10-log |
+------------+
1 row in set (0.00 sec)
db83-3306>>create user test_user@'%' identified by 'test_user';
Query OK, 0 rows affected (0.00 sec)
使用 localhost 登录
[mysql@mysql-test-83 ~]$ /usr/local/mysql57/bin/mysql -utest_user -p -hlocalhost
Enter password:
ERROR 1045 (28000): Access denied for user 'test_user'@'localhost' (using password: YES)
使用 IP 登录
[mysql@mysql-test-83 ~]$ /usr/local/mysql57/bin/mysql -utest_user -p -h127.0.0.1
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.6.10-log MySQL Community Server (GPL)
========= 省略 ===========
mysql> status
--------------
/usr/local/mysql57/bin/mysql Ver 14.14 Distrib 5.7.21, for linux-glibc2.12 (x86_64) using EditLine wrapper
Connection id: 3
Current database:
Current user: test_user@127.0.0.1
SSL: Not in use
Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server version: 5.6.10-log MySQL Community Server (GPL)
Protocol version: 10
Connection: 127.0.0.1 via TCP/IP
......
--------------
结果显示MySQL 5.6的%不包括localhost
3.4 MySQL 5.1
创建用户
mysql> select version();
+-----------+
| version() |
+-----------+
| 5.1.73 |
+-----------+
1 row in set (0.00 sec)
mysql> create user test_user@'%' identified by 'test_user';
Query OK, 0 rows affected (0.00 sec)
使用 localhost 登录
[root@chengqm ~]# mysql -utest_user -p
Enter password:
ERROR 1045 (28000): Access denied for user 'test_user'@'localhost' (using password: YES)
使用 IP 登录
[root@chengqm ~]# mysql -utest_user -p -h127.0.0.1
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4901339
Server version: 5.1.73 Source distribution
========= 省略 ===========
mysql> status
--------------
mysql Ver 14.14 Distrib 5.1.73, for redhat-linux-gnu (x86_64) using readline 5.1
Connection id: 4901339
Current database:
Current user: test_user@127.0.0.1
SSL: Not in use
Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server version: 5.1.73 Source distribution
Protocol version: 10
Connection: 127.0.0.1 via TCP/IP
结果显示 5.1 版本的%不包括localhost
3.5 MariaDB 10.3
创建用户
db83-3306>>select version();
+---------------------+
| version() |
+---------------------+
| 10.3.11-MariaDB-log |
+---------------------+
1 row in set (0.000 sec)
db83-3306>>create user test_user@'%' identified by 'test_user';
Query OK, 0 rows affected (0.001 sec)
使用 localhost 登录
[mysql@mysql-test-83 ~]$ /usr/local/mariadb/bin/mysql -utest_user -p -hlocalhost
Enter password:
ERROR 1045 (28000): Access denied for user 'test_user'@'localhost' (using password: YES)
使用 IP 登录
[mysql@mysql-test-83 ~]$ /usr/local/mariadb/bin/mysql -utest_user -p -h127.0.0.1
Enter password:
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 12
Server version: 10.3.11-MariaDB-log MariaDB Server
========= 省略 ===========
MariaDB [(none)]> status
--------------
/usr/local/mariadb/bin/mysql Ver 15.1 Distrib 10.3.11-MariaDB, for Linux (x86_64) using readline 5.1
Connection id: 12
Current database:
Current user: test_user@127.0.0.1
SSL: Not in use
Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server: MariaDB
Server version: 10.3.11-MariaDB-log MariaDB Server
Protocol version: 10
Connection: 127.0.0.1 via TCP/IP
结果显示MariaDB 10.3的%不包括localhost
4 结论
| 版本 |
用户中的%是否包括localhost |
| MySQL8.0 |
包括 |
| MySQL5.7 |
包括 |
| MySQL5.6 |
不包括 |
| MySQL5.1 |
不包括 |
| MariaDB 10.3 |
不包括 |
好了，这篇文章就介绍到了，希望大家以后多多支持脚本之家。
您可能感兴趣的文章:- 如何快速修改MySQL用户的host属性
- mysql允许所有host访问的方法
- 完美解决MySQL通过localhost无法连接数据库的问题
- MySQL 可以用localhost 连接，但不能用IP连接的问题解决方法
- 浅谈Mysql连接数据库时host和user的匹配规则
咨 询 客 服