LARAVEL framework and Eloquent ORM model - laravel

Question

{ "_id" : 8751, "title" : "The Banquet", "author" : "Dante", "copies" : 2 }
{ "_id" : 8752, "title" : "Divine Comedy", "author" : "Dante", "copies" : 1 }
{ "_id" : 8645, "title" : "Eclogues", "author" : "Dante", "copies" : 2 }
{ "_id" : 7000, "title" : "The Odyssey", "author" : "Homer", "copies" : 10 }
{ "_id" : 7020, "title" : "Iliad", "author" : "Homer", "copies" : 10 }
Above is a 'books' table
Using LARAVEL framework and Eloquent ORM model, how to return the following result:
{ "author" : "Homer", "books" : [ "The Odyssey", "Iliad" ] }
{ "author" : "Dante", "books" : [ "The Banquet", "Divine Comedy", "Eclogues" ] }
I am learning Laravel.

Answer 1

You could use GROUP_CONCAT.
Book::groupBy('author')
->select(DB::raw('GROUP_CONCAT(title) as books'), 'author')
->get()
->map(function ($author) {
$author->books = preg_split('/,/', $author->books);
return $author;
});
This will get you:
{ "author" : "Homer", "books" : [ "The Odyssey", "Iliad" ] }
{ "author" : "Dante", "books" : [ "The Banquet", "Divine Comedy", "Eclogues" ] }

Answer 2

If the table structure is within your control, then the better solution would be to place the data into two tables books and authors, to avoid data duplication as is the case now with a single table.
Then define two Eloquent Models and setup a one-to-many relationship. As in one author can have many books written.
So the Book model might look like this:
class Book extends Model
{
public function author()
{
return $this->belongsTo(Author::class);
}
}
And the Author model might look like this:
class Author extends Model
{
public function books()
{
return $this->hasMany(Book::class);
}
}
Now you can use the relationship, eager loading and a little collection processing to fetch the data in your preferred format:
$authors = Author::with('books')->get()->map(function ($author) {
return [
'author' => $author->name,
'books' => $author->books->pluck('title')
];
});
You might also want to read up on Database Normalization, and in your case more specifically The 1st Normal Form.