Laravel Eloquent LEFT JOIN WHERE NULL

This can be resolved by specifying the specific column names desired from the specific table like so:

$c = Customer::leftJoin('orders', function($join) {
      $join->on('customers.id', '=', 'orders.customer_id');
    })
    ->whereNull('orders.customer_id')
    ->first([
        'customers.id',
        'customers.first_name',
        'customers.last_name',
        'customers.email',
        'customers.phone',
        'customers.address1',
        'customers.address2',
        'customers.city',
        'customers.state',
        'customers.county',
        'customers.district',
        'customers.postal_code',
        'customers.country'
    ]);

You can also specify the columns in a select like so:

$c = Customer::select('*', DB::raw('customers.id AS id, customers.first_name AS first_name, customers.last_name AS last_name'))
->leftJoin('orders', function($join) {
  $join->on('customers.id', '=', 'orders.customer_id') 
})->whereNull('orders.customer_id')->first();

Although Other Answers work well, i want to give you alternate short version which i use very often:

Customer::select('customers.*')
        ->leftJoin('orders', 'customers.id', '=', 'orders.customer_id')
        ->whereNull('orders.customer_id')->first();

And as in laravel version 5.3 added one more feature which will make your work even simpler look below for example:

Customer::doesntHave('orders')->get();