对于任何试图创建一个新的db连接而不是在laravel上，而是在这里寻找从终端运行PDO的答案的人。这对你有帮助。你可以重构它，使其最适合你。

<?php

class db
{
   private $DBHOST = 'localhost'; // you don't need 127.0.0.1
   private $DRIVER = 'mysql';
   private $PORT   = '8888'; // database port. 8888 is mine
   private $DB     = 'example-db';
   private $PASS   = 'example-pass';
   private $USER   = 'root';
   private $SOCKS  = ''; // can fill this or leave blank.


   // - connect (dummy connection)
   private function con()
   {
       if ($this->SOCKS == '')
       {
           // run shell command to get 
           $socks = shell_exec('netstat -ln | grep mysql');
           $socks = trim(substr($socks, strpos($socks, '/')));

           $this->SOCKS = strlen($socks) > 0 ? ';unix_socket='.$socks : '';
       }
       else
       {
          $this->SOCKS = ';unix_socket='.$this->SOCKS;
       }

       $dsn = $this->DRIVER.':host='.$this->DBHOST.';dbname='.$this->DB;

       // add socks
       $dsn .= $this->SOCKS;

       // add port
       $dsn .= (strlen($this->PORT) > 0) ? ';port='.$this->PORT : '';

       // extablish connection
       $con = new PDO($dsn, $user, $pass);

       // return PDO instance.
       return $con;
   }
   // - ends here

   // now you can call $this->con() within class to use connection 
   // would run fine on any terminal

} 

希望能有所帮助!

要添加到@alexventuraio的解决方案中，如果你在Laravel 5.8上遇到了这个问题，你可能想要替换数据库配置文件中'unix_socket'的值，如下:

 'mysql' => [
        'driver' => 'mysql',
        'host' => env('DB_HOST', '127.0.0.1'),
        'port' => env('DB_PORT', '3306'),
        'database' => env('DB_DATABASE', 'forge'),
        'username' => env('DB_USERNAME', 'forge'),
        'password' => env('DB_PASSWORD', ''),
        // 'unix_socket' =>'/var/run/mysqld/mysqld.sock',
        'unix_socket' => env('DB_SOCKET', ''), // replace with this line, so you can always add the mysqld.sock from the dotenv file
        'charset' => 'utf8mb4',
        'collation' => 'utf8mb4_unicode_ci',
        'prefix' => '',
        'prefix_indexes' => true,
        'strict' => false,
        'engine' => null,
        'options' => extension_loaded('pdo_mysql') ? array_filter([
            PDO::MYSQL_ATTR_SSL_CA => env('MYSQL_ATTR_SSL_CA'),
        ]) : [],
    ],

在Laravel 5中，数据库用户名和密码保存在项目目录中的.env文件中，例如。

DB_HOST=127.0.0.1
DB_DATABASE=db1
DB_USERNAME=user1
DB_PASSWORD=pass1

正如你所看到的，这些环境变量覆盖了这里的“forge”字符串，所以改变它们没有任何影响:

    'mysql' => [
        'driver'    => 'mysql',
        'host'      => env('DB_HOST', 'localhost'),
        'database'  => env('DB_DATABASE', 'forge'),
        'username'  => env('DB_USERNAME', 'forge'),
        'password'  => env('DB_PASSWORD', ''),
        'charset'   => 'utf8',
        'collation' => 'utf8_unicode_ci',
        'prefix'    => '',
        'strict'    => false,
    ],

更多信息请访问https://mattstauffer.co/blog/laravel-5.0-environment-detection-and-environment-variables

如果您正在使用Laravel Homestead，请确保您正在调用服务器上的命令。

homestead ssh

然后简单地cd到正确的目录并在那里发出命令。

如果有人还在寻找答案，只要检查你的。env文件。出于某种原因，laravel创建了一个。env。示例文件，所以所有这些答案都不适合我。我修复了重命名。env的问题。.env的示例

在我的情况下，我没有任何问题，只是忘记启动mysql服务…

sudo service mysqld start