Question

我想根据我的数据库结构了解排名：

我有一个模型Post属于一个名为Edition的模型（也一个 Edition 有很多 {{1 }}。

一个Post有很多Post。

我想根据特定Like内的Post个计数来了解Like的排名。

代码：

Edition

对于不熟悉// Define the id of an edition $edition_id = 53; // The id of the post to retrieve rank $post_id = 132; // Compose the query by select all posts, of interested edition ... $query = App\Models\Post::where('edition_id', $edition_id) // ... with like count (this produce an additional field named likes_count) ... ->withCount('likes') // ... in descendig order by this count. ->orderBy('likes_count', 'desc'); // By execute it I can get right results. $query->get();的人，我报告从上面的代码执行的sql查询：

Laravel Eloquent ORM

我报告查询结果：

select `posts`.*, (select count(*) from `likes` where `posts`.`id` = `likes`.`post_id` and `likes`.`deleted_at` is null) as `likes_count`
from `posts`
where `edition_id` = '53' and `posts`.`deleted_at` is null
order by `likes_count` desc

如何从组合查询的结果中获取具有特定=> Illuminate\Database\Eloquent\Collection {#994 all: [ App\Models\Post {#993 id: 135, likes_count: 4, }, App\Models\Post {#1075 id: 134, likes_count: 3, }, App\Models\Post {#1091 id: 133, likes_count: 2, }, App\Models\Post {#997 id: 132, likes_count: 1, }, App\Models\Post {#1038 id: 131, likes_count: 0, }, ], }的记录的行位置？

例如，如何使用id检索记录的排名结果？

Answer 1

您可以使用子查询：

$query = Post::where('edition_id', $edition_id)
    ->withCount('likes')
    ->selectRaw('@rank := @rank + 1 rank')
    ->from(DB::raw('`posts`, (SELECT @rank := 0) vars'))
    ->orderBy('likes_count', 'desc');

$posts = Post::fromSub($query, 'posts')->paginate();

$post = Post::fromSub($query, 'posts')->find($post_id);

Laravel <5.6的解决方法：

Builder::macro('fromSub', function($query, $as) {
    $this->bindings = array_merge(
        array_slice($this->bindings, 0, 1),
        ['from' => $query->getBindings()],
        array_slice($this->bindings, 1)
    );

    $sql = '('.$query->toSql().') as '.$this->grammar->wrap($as);

    return $this->from(DB::raw($sql));
});

Answer 2

您可以使用search()方法来找到密钥：

搜索方法在集合中搜索给定的值，如果找到，则返回其键。如果找不到该项目，则返回false。

$id = 132;

$key = $query->search(function($post,$id) {
    return $post->id === $id;
});

口才/ SQL-获取查询的行号（排名）

2 个答案: