How to Correctly Calculate Sum with GroupBy in Laravel Eloquent?

Calculating Sum with GroupBy in Laravel Eloquent

In Laravel, the Eloquent ORM offers a powerful way to interact with the database. One common task is to calculate the sum of a column while grouping by a specific field. While using the sum() method seems straightforward, it can lead to errors due to the order of execution.

Incorrect Approach

$this->data['no_of_pages'] = Document::sum('no_of_pages')
                            ->groupBy('users_editor_id'); // Call to undefined method

In the above code, the groupBy() method is called after the sum() method, which causes an error because sum() executes the query and returns the result before groupBy() can be applied.

Correct Solutions

To calculate the sum with groupBy correctly, use the following approaches:

Approach 1 (Recommended)

Document::groupBy('users_editor_id')
    ->selectRaw('sum(no_of_pages) as sum, users_editor_id')
    ->pluck('sum', 'users_editor_id');

This method uses the selectRaw() method to create an alias for the calculated sum (sum). Then, the pluck() method extracts the sum and users_editor_id fields, providing an associative array result.

Approach 2

Document::groupBy('users_editor_id')
    ->selectRaw('*, sum(no_of_pages) as sum')
    ->get();

This method creates a pseudo-ORM result by adding a sum field to each document model. However, it's less desirable because the result is not a true ORM collection.

The above is the detailed content of How to Correctly Calculate Sum with GroupBy in Laravel Eloquent?. For more information, please follow other related articles on the PHP Chinese website!