laravel where or where and where code example

Example 1: laravel with and where

$projects = Project::whereHas('projectOffers', function ($offer) {
            $offer->where('teacher_id', "Ahmed");
            $offer->where('status_id', "Accepted");
        })->where('status_id', "inprogress")->get();

Example 2: or where in orm laravel

$a='foo', $b='bar', $c='john', $d='doe';

Coder::where(function ($query) use ($a, $b) {
    $query->where('a', '=', $a)
          ->orWhere('b', '=', $b);
})->where(function ($query) use ($c, $d) {
    $query->where('c', '=', $c)
          ->orWhere('d', '=', $d);
})->get();

Example 3: laravel where

$users = DB::table('users')
                ->whereDate('created_at', '2016-12-31')
                ->get();