Sorting of columns by joining two tables in Laravel

I have two tables books and publishers. publisher_id is primary key in publishers table and foreign key in books table. In index.blade.php of books, I want to create link for sorting of columns of book index. here is my that part of index.blade.php view where I am creating links.

<table class="table">
        <tr>
            <th><a href="{{ route('books-index',['sort' => 'name','direction' => 'asc']) }}">Name</a></th>
            <th><a href="{{ route('books-index',['sort' => 'published_date','direction' => 'asc']) }}">Published Date</a></th>
            <th><a href="{{ route('books-index',['sort' => 'publisher_name','direction' => 'asc']) }}">Publisher Name</a></th>
            <th>Category</th>
            <th>Author</th>

And in BooksController.php, I have my index method in which sorting part is given below

public function index(Request $request) {
        $input = $request->all();
        $sort = 'created_at';
        $direction = 'desc';
        if(isset($input['sort'])){
            $sort = $input['sort'];
        }
        if(isset($input['direction'])){
            $direction = $input['direction'];
        }

        $books = Book::join('publishers','publishers.id','books.publisher_id')
                ->orderby($sort,$direction)->select('books.*')->paginate(5);

Below is given my index view of books

But When I click on publisher_name for sorting, it gives me an error like this.

QueryException in Connection.php line 770:
SQLSTATE[42S22]: Column not found: 1054 Unknown column 'publisher_name' in 'order clause' (SQL: select `books`.* from `books` inner join `publishers` on `publishers`.`id` = `books`.`publisher_id` order by `publisher_name` asc limit 5 offset 0)

So what can I do to solve it?

Answer

You can alias publishers.name to publisher_name, so that mysql can find the alias column:

$books = Book::join('publishers','publishers.id','books.publisher_id')
                ->orderBy($sort,$direction)->selectRaw('books.*, publishers.name AS publisher_name')->paginate(5);