centos安装LAMP环境时访问本地MYSQL数据库错误

近日在安装LAMP环境时访问本地MYSQL数据库错误

错误如下：

Warning: mysqli::mysqli(): (HY000/2002): Can't connect to local MySQL server

问题描述：

由于将安装mysql服务器文件位置修改在home目录下，造成本地访问问题。

在网上找了很久终于找到解决问题的方法：

1、先确保在本机上使用命令能登陆，如果也出现提示sock文件位置问题，那么需要修改mysql配置文件（/etc/my.cnf）

增加如下配置：

[mysql]

socket=/home/mysqldata/mysql.sock#这是我的sock文件的位置

2、php使用mysqli无法访问问题

解决方法：

找到PHP配置文件(/etc/php.ini)找到mysqli.default_socket这个值

修改为mysqli.default_socket =/home/mysqldata/mysql.sock#这是我的sock文件的位置

问题分析（这是我在网上找到的解决方案）：

On Unix, MySQL programs treat the host name localhost specially, in a way that is likely different from what you expect compared to other network-based programs. For connections to localhost, MySQL programs attempt to connect to the local server by using a Unix socket file. This occurs even if a --port or -P option is given to specify a port number. To ensure that the client makes a TCP/IP connection to the local server, use --host or -h to specify a host name value of 127.0.0.1, or the IP address or name of the local server. You can also specify the connection protocol explicitly, even for localhost, by using the --protocol=TCP option.

其实就是说UNIX系统需要将localhost 这个地址进行转换的文件

解决的方法其他有三个

There are a few ways to solve this problem.

1. You can just use TCP/IP instead of the Unix socket. You would do this by using 127.0.0.1instead of localhost when you connect. The Unix socket might by faster and safer to use, though.

2. You can change the socket in php.ini: open the MySQL configuration file my.cnf to find where MySQL creates the socket, and set PHP's mysqli.default_socket to that path. On my system it's /var/run/mysqld/mysqld.sock.

3. Configure the socket directly in the PHP script when opening the connection. For example:

   $db = new MySQLi('localhost', 'kamil', '***', '', 0, 
                                 '/var/run/mysqld/mysqld.sock')

1、修改连接文件中localhost 为127.0.0.1

2、查看my.cnf文件中sock文件的位子，并赋值到php.ini:文件中的mysqli.default_socket去

3、PHP语言直接多一个参数指向sock文件位置。