在嵌套关系上添加列

Question

是否可以在嵌套关系上添加列？

例如，我有以下表格

groups
- id
- title

categories
- id
- title
- parent_id
- group_id

threads
- id
- title
- replies_count
- category_id

我想做以下事情

class GroupController extends Controller {

public function index(){
return Groups::with(['categories'])->get()
}

class Category extends Model{

protected $withCount = ['threads'];
}

因此，当我预先加载 'categories' 时，我也会预先加载与每个类别关联的每个线程。但我还想在类别模型上添加一个新列，其中一些 replies_count，与 withCount.

相同

例如

groups => [
"id" => 1,
"title" => "some-title"
"categories" => [
 "id" => 1,
 "title" => "category-title",
 "threads_count" => 2,
 "replies_count_sum" => 5
  ]
]

在上面的示例中，具有 id=1 的 group 具有关联的 category与之相关，并且该类别有 2 个线程 与之相关联，并且这两个线程上的回复总数为 5

Answer 1

你应该可以使用 withCount and sub Query Join

$values=Group::with(['categories'=>function($query)use(
{
$repliesSumCountForCategory=Threads::selectRaw('category_id,sum(replies_count) as replies_count_sum')->groupBy('category_id');

   $query->withCount('threads');
   $query->join($repliesSumCountForCategory,'replies_sum_count_for_category',
function($join)
{
$join->on('categories.id','=','replies_sum_count_for_category.category_id')
}
$query->addSelect('replies_sum_count_for_category.replies_count_sum');
}
])->get();

我没有机会测试它，如果有帮助请告诉我...

在嵌套关系上添加列

add column on a nested relationship

laravel

eloquent

eloquent-relationship