laravel Laravel属于许多没有其中之一的
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Laravel belongsToMany where doesn't have one of
提问by Karl
I have two tables: categoriesand videos, I then have a pivot table for these as it's a belongsToMany relationship.
我有两个表：categoriesand videos，然后我有一个数据透视表，因为它是一个belongsToMany关系。
What I'm trying to do is get all of the videos where there isn't a single instance of the video being in one of many categories.
我想要做的是获取所有视频，其中没有一个视频实例属于多个类别之一。
e.g.
例如
- Video 1 is in category 1, 2 and 3.
- Video 2 is in category 1 and 3.
- Video 3 is in category 1.
- 视频 1 属于类别 1、2 和 3。
- 视频 2 属于类别 1 和类别 3。
- 视频 3 属于类别 1。
I want to get the video which is NOT in category 2 or 3, meaning this will return Video 3.
我想获得不在类别 2 或 3 中的视频，这意味着这将返回视频 3。
What I've tried so far, which doesn't give the intended result, this is because another row is still found for Video 1 and 2, as they are in Category 1:
到目前为止我已经尝试过，但没有给出预期的结果，这是因为视频 1 和 2 仍然存在另一行，因为它们在类别 1 中：
Video::whereHas('categories', function($query) {
$query->whereNotIn('category_id', [2,3]);
})->take(25)->get();
The query populated from this is:
由此填充的查询是：
select * from `videos` where exists (select * from `categories` inner join
`category_video` on `categories`.`id` = `category_video`.`category_id` where
`videos`.`id` = `category_video`.`video_id` and `category_id` != ? and
`category_id` != ? and `categories`.`deleted_at` is null) and `videos`.`deleted_at`
is null order by `created_at` desc limit 25
回答by jedrzej.kurylo
You can use Eloquent's whereDoesntHave()constraint to get what you need:
您可以使用Eloquent的whereDoesntHave()约束来获取您需要的内容：
// get all Videos that don't belong to category 2 and 3
Video::whereDoesntHave('categories', function($query) {
$query->whereIn('id', [2, 3]);
})->get();
