'mysql' => [
            'driver' => 'mysql',
            'host' => env('DB_HOST', '127.0.0.1'),
            'port' => env('DB_PORT', '3306'),
            'database' => env('DB_DATABASE', 'db1'),
            'username' => env('DB_USERNAME', 'root'),
            'password' => env('DB_PASSWORD', ''),
            ...
        ],

        'mysql2' => [
            'driver' => 'mysql',
            'host' => env('DB_HOST_2', '127.0.0.1'),
            'port' => env('DB_PORT_2', '3306'),
            'database' => env('DB_DATABASE_2', 'db2'),
            'username' => env('DB_USERNAME_2', 'root'),
            'password' => env('DB_PASSWORD_2', ''),
         ...
        ],

$user= DB::connection("mysql2")->table('User')
        ->join('ticket', 'User.Id', '=','ticket.user_id')
        ->select('User.*')
        ->where('ticket.id', '=', 1)
        ->get();

CREATE VIEW `D2`.`example` AS SELECT * FROM `D1`.`T1`;