how to use orwhere null column in laravel query code example

Example 1: laravel not in query

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

Example 2: laravel orWhere

$camps = $field->camps()->where('status', 0)->where(function ($q) {
    $q->where('sex', Auth::user()->sex)->orWhere('sex', 0);
})->get();