laravel lumen use 2 databases

First, you'll need to configure your connections. If you don't already have one you'll need to create a config directory in your project and add the file config/database.php. It might look like this:

<?php

return [

   'default' => 'accounts',

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

        'mysql2' => [
            'driver'    => 'mysql',
            'host'      => env('DB2_HOST'),
            'port'      => env('DB_PORT'),
            'database'  => env('DB2_DATABASE'),
            'username'  => env('DB2_USERNAME'),
            'password'  => env('DB2_PASSWORD'),
            'charset'   => 'utf8',
            'collation' => 'utf8_unicode_ci',
            'prefix'    => '',
            'strict'    => false,
        ],
    ],
];
Once you've added your connection configurations, you can access them by getting the database manager object out of the container and calling ->connection('connection_name').

// Use default connection
app('db')->connection()->select('xx');
DB::connection()->select('yy');

// Use mysql2 connection
app('db')->connection('mysql2')->select('xx');
DB::connection('mysql2')->select('yy');
Hope this helps you!!