joins in laravel eloquent code example

Example 1: laravel not in query

DB::table(..)->select(..)->whereNotIn('book_price', [100,200])->get();

Example 2: join in laravel eloquent

$customer = DB::table('customers')
                ->join('shops', 'customers.shop_id', '=', 'shops.shop_id')
                ->where('customer_contact', $contact_no)
                ->get();