如何查看mysql 默认端口号和修改端口号

1. 登录mysql

[root@test /]# mysql -u root -p
Enter password:

2. 使用命令show global variables like 'port';查看端口号

mysql> show global variables like 'port';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port | 3306 |
+---------------+-------+
1 row in set (0.00 sec)

3. 修改端口，编辑/etc/my.cnf文件，早期版本有可能是my.conf文件名，增加端口参数，并且设定端口，注意该端口未被使用，保存退出。

[root@test etc]# vi my.cnf
[mysqld]
port=3506
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql

Disabling symbolic-links is recommended to prevent assorted security risks

symbolic-links=0

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

"my.cnf" 11L, 261C written
[root@test etc]#

4. 重新启动mysql

[root@test ~]# /etc/init.d/mysqld restart
Stopping mysqld: [ OK ]
Starting mysqld: [ OK ]

5.再次登录后检查端口已修改为’3506’.

[root@test etc]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.1.66 Source distribution

Copyright (c) 2000, 2012, 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> show global variables like 'port';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port | 3506 |
+---------------+-------+
1 row in set (0.00 sec)

mysql>

总结：注意修改的端口不要被占用，而且要有规划，不要轻意的总是调整数据库端口。还有就是安全保障，记得与负责网络的人提前通知，以免端口无法正常使用。