Laravel 实现 groupBy 查询分组数量

如何用laravel来实现以下sql呢？

select `book_name`, count(*) as num from `clock_books` group by `book_name`

可使用laravel的原始表达式DB::raw()来操作：

$books = DB::table('books')
    ->select('book_name', DB::raw('count(*) as num'))
    ->groupBy('book_name')
    ->get();
||    

$users = DB::table('books')
 ->select(DB::raw('count(*) as num, book_name'))
 ->groupBy('book_name')
 ->get();