如何理解MySQL用户中的百分号%是否包含localhost

这篇文章主要介绍"如何理解MySQL用户中的百分号%是否包含localhost"，在日常操作中，相信很多人在如何理解MySQL用户中的百分号%是否包含localhost问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答"如何理解MySQL用户中的百分号%是否包含localhost"的疑惑有所帮助！接下来，请跟着小编一起来学习吧！

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 -hlocalhostEnter 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 wrapperConnection id:        9Current database:    Current user:        test_user@localhostSSL:            Not in useCurrent pager:        stdoutUsing outfile:        ''Using delimiter:    ;Server version:        5.7.21-log MySQL Community Server (GPL)Protocol version:    10Connection:        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 -h227.0.0.1Enter 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 wrapperConnection id:        11Current database:    Current user:        test_user@127.0.0.1SSL:            Cipher in use is DHE-RSA-AES256-SHACurrent pager:        stdoutUsing outfile:        ''Using delimiter:    ;Server version:        5.7.21-log MySQL Community Server (GPL)Protocol version:    10Connection:        127.0.0.1 via TCP/IPServer 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 -hlocalhostEnter password: Welcome to the MySQL monitor.  Commands end with ; or \g.Your MySQL connection id is 9Server 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:        9Current database:    Current user:        test_user@localhostSSL:            Not in useCurrent pager:        stdoutUsing outfile:        ''Using delimiter:    ;Server version:        8.0.11 MySQL Community Server - GPLProtocol version:    10Connection:        Localhost via UNIX socket...

使用 IP 登录

[root@mysql-test-72 ~]# /usr/local/mysql80/bin/mysql -utest_user -p -h227.0.0.1Enter password: Welcome to the MySQL monitor.  Commands end with ; or \g.Your MySQL connection id is 8Server 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:        8Current database:    Current user:        test_user@127.0.0.1SSL:            Cipher in use is DHE-RSA-AES128-GCM-SHA256Current pager:        stdoutUsing outfile:        ''Using delimiter:    ;Server version:        8.0.11 MySQL Community Server - GPLProtocol version:    10Connection:        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 wrapperConnection id:        9Current database:    Current user:        test_user@localhostSSL:            Not in useCurrent pager:        stdoutUsing outfile:        ''Using delimiter:    ;Server version:        5.7.21-log MySQL Community Server (GPL)Protocol version:    10Connection:        Localhost via UNIX socket....

使用 IP 登录

[mysql@mysql-test-83 ~]$ /usr/local/mysql57/bin/mysql -utest_user -p -h227.0.0.1Enter 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 wrapperConnection id:        11Current database:    Current user:        test_user@127.0.0.1SSL:            Cipher in use is DHE-RSA-AES256-SHACurrent pager:        stdoutUsing outfile:        ''Using delimiter:    ;Server version:        5.7.21-log MySQL Community Server (GPL)Protocol version:    10Connection:        127.0.0.1 via TCP/IPServer 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 -hlocalhostEnter 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 -h227.0.0.1Enter password: Welcome to the MySQL monitor.  Commands end with ; or \g.Your MySQL connection id is 3Server 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 wrapperConnection id:        3Current database:    Current user:        test_user@127.0.0.1SSL:            Not in useCurrent pager:        stdoutUsing outfile:        ''Using delimiter:    ;Server version:        5.6.10-log MySQL Community Server (GPL)Protocol version:    10Connection:        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 -pEnter 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 -h227.0.0.1Enter password: Welcome to the MySQL monitor.  Commands end with ; or \g.Your MySQL connection id is 4901339Server 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 5.1Connection id:        4901339Current database:    Current user:        test_user@127.0.0.1SSL:            Not in useCurrent pager:        stdoutUsing outfile:        ''Using delimiter:    ;Server version:        5.1.73 Source distributionProtocol version:    10Connection:        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 -hlocalhostEnter 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 -h227.0.0.1Enter password: Welcome to the MariaDB monitor.  Commands end with ; or \g.Your MariaDB connection id is 12Server 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 5.1Connection id:        12Current database:    Current user:        test_user@127.0.0.1SSL:            Not in useCurrent pager:        stdoutUsing outfile:        ''Using delimiter:    ;Server:            MariaDBServer version:        10.3.11-MariaDB-log MariaDB ServerProtocol version:    10Connection:        127.0.0.1 via TCP/IP

结果显示MariaDB 10.3的%不包括localhost

4 结论

到此，关于"如何理解MySQL用户中的百分号%是否包含localhost"的学习就结束了，希望能够解决大家的疑惑。理论与实践的搭配能更好的帮助大家学习，快去试试吧！若想继续学习更多相关知识，请继续关注网站，小编会继续努力为大家带来更多实用的文章！