Combining multiple results when joining tables: a step-by-step guide

Question

I have a query that returns the names of categories and their subcategories.

$subcategories = Subcategory::select('subcategories.name as subcatname', 'categories.name as catname')
                ->join('categories', 'subcategories.idCategory', '=', 'categories.id')
                ->get();

Now the results I get are as follows:

'Music' => 'Jazz',
'Music' => 'Rock',
'Music' => 'Pop',
'Movie' => 'Action'

How can I group it like this:

'Music' => array('Jazz', 'Rock','Pop'),
'Movies' => array('Action')

Is it possible without too many loop iterations and check which subcategory belongs to which category?

Answer 1

You can use laravelCollections

First you need to group by the groupBy method, then map each group and merge each sub-array.

$result = collect($subcategories)
        ->groupBy('catname')
        ->map(function ($item) {
            return array_merge($item->toArray());
        })->all();