Laravel中按求和列关系排序 [英] Order by sum column relationship in Laravel

问题描述

我有这个控制器，它从发布表中获取发布. posts 表中的每个帖子与另一个表 likes 都具有"hasMany"关系.

I have this controller which grabs posts from a post table. Every post in the posts table have the relation "hasMany" with another table likes.

控制器:

public function getDashboard(){
        $posts = Post::orderBy('created_at', 'desc')->get(); 

        return view('dashboard', ['posts' => $posts]);
}

我想用以下内容代替创建于":

I'd like to replace 'created at' with something like:

$post->likes->sum(like)

虽然不知道如何编写正确的语法.

Don't know how to write the right syntax though.

这是桌子.

Posts  
--id   
--body  
Likes 
--id  
--post_id  
--like

like 列的值可以为1或-1. 我想为每个帖子按该列的总和排序. 因此，一个具有dislike(-1)和一个like(1)的帖子的合计值为0，因此将放置在一个具有like(1)的帖子之后.

The column like can have the value 1 or -1. I'd like to order on the summation of that column for each post. So a post with one dislike(-1) and one like(1) will have the aggregated value of 0, hence will be placed after a post with one like(1).

推荐答案

您可以使用

You can use withCount() for this as:

Post::withCount('likes')->orderBy('likes_count')->get()

withCount()将在您产生的结果上放置一个{relation} _count列 型号

withCount() will place a {relation}_count column on your resulting models

更新

Post::withCount(['likes' => function($q) {
    $q->where('like', 1)
}])
->orderBy('likes_count')
->get()

Update2

您可以使用 sortByDesc() 对您的收藏进行排序:

You can use sortByDesc() to sort your collection as:

$posts = Post::get();

$posts = $posts->sortByDesc(function ($post) {
            return $post->likes->sum('like');
        });

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