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

推荐学习：《mysql视频教程》

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