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- Don’t Filter by NULL in Collections
- Use groupBy on Collections with Custom Callback Function
- Multiple Collection Methods in a Row
- Calculate Sum with Pagination
- Serial no. in foreach loop with pagination
- Higher order collection methods
- Higher order collection message
You can filter by NULL in Eloquent, but if you're filtering the collection further - filter by empty string, there's no "null" in that field anymore.
// This works
$messages = Message::where('read_at is null')->get();
// Won’t work - will return 0 messages
$messages = Message::all();
$unread_messages = $messages->where('read_at is null')->count();
// Will work
$unread_messages = $messages->where('read_at', '')->count();
If you want to group result by some condition which isn’t a direct column in your database, you can do that by providing a closure function.
For example, if you want to group users by day of registration, here’s the code:
$users = User::all()->groupBy(function($item) {
return $item->created_at->format('Y-m-d');
});
Collection
class, so performed AFTER the results are fetched from the database.
If you query all results with ->all()
or ->get()
, you may then perform various Collection operations on the same result, it won’t query database every time.
$users = User::all();
echo 'Max ID: ' . $users->max('id');
echo 'Average age: ' . $users->avg('age');
echo 'Total budget: ' . $users->sum('budget');
How to calculate the sum of all records when you have only the PAGINATED collection? Do the calculation BEFORE the pagination, but from the same query.
// How to get sum of post_views with pagination?
$posts = Post::paginate(10);
// This will be only for page 1, not ALL posts
$sum = $posts->sum('post_views');
// Do this with Query Builder
$query = Post::query();
// Calculate sum
$sum = $query->sum('post_views');
// And then do the pagination from the same query
$posts = $query->paginate(10);
We can use foreach collection items index as serial no (SL) in pagination.
...
<th>Serial</th>
...
@foreach ($products as $product)
<tr>
<td>{{ $loop->index + $product->firstItem() }}</td>
...
@endforeach
it will solve the issue of next pages(?page=2&...) index count from continue.
Collections also provide support for "higher order messages", which are short-cuts for performing common actions on collections. This example calculates the price per group of products on an offer.
$offer = [
'name' => 'offer1',
'lines' => [
['group' => 1, 'price' => 10],
['group' => 1, 'price' => 20],
['group' => 2, 'price' => 30],
['group' => 2, 'price' => 40],
['group' => 3, 'price' => 50],
['group' => 3, 'price' => 60]
]
];
$totalPerGroup = collect($offer['lines'])->groupBy->group->map->sum('price');