$users = DB::table('users')->where('name', 'John')->get();

$users = DB::table('users')->where('name', 'John')->orWhere('name', 'Jane')->get();

$users = DB::table('users')->whereBetween('age', [20, 30])->get();

$users = DB::table('users')->whereIn('id', [1, 2, 3])->get();

$users = DB::table('users')->whereNull('email')->get();
$users = DB::table('users')->whereNotNull('email')->get();

$users = DB::table('users')
    ->whereExists(function ($query) {
        $query->select(DB::raw(1))
              ->from('posts')
              ->whereRaw('posts.user_id = users.id');
    })
    ->get();

$role = 'admin';

$users = DB::table('users')
    ->when($role, function ($query, $role) {
        return $query->where('role', $role);
    })
    ->get();

$users = DB::table('users')
    ->where('status', 'active')
    ->where(function ($query) {
        $query->where('name', 'John')
              ->orWhere('age', '>', 30);
    })
    ->get();