Laravel orderBy 上的关系
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Laravel orderBy on a relationship
提问by PrestonDocks
I am looping over all comments posted by the Author of a particular post.
我正在遍历特定帖子的作者发布的所有评论。
foreach($post->user->comments as $comment)
{
echo "<li>" . $comment->title . " (" . $comment->post->id . ")</li>";
}
This gives me
这给了我
I love this post (3)
This is a comment (5)
This is the second Comment (3)
How would I order by the post_id so that the above list is ordered as 3,3,5
我将如何按 post_id 排序，以便将上述列表排序为 3,3,5
回答by Rob Gordijn
It is possible to extend the relation with query functions:
可以使用查询函数扩展关系：
<?php
public function comments()
{
return $this->hasMany('Comment')->orderBy('column');
}
[edit after comment]
[评论后编辑]
<?php
class User
{
public function comments()
{
return $this->hasMany('Comment');
}
}
class Controller
{
public function index()
{
$column = Input::get('orderBy', 'defaultColumn');
$comments = User::find(1)->comments()->orderBy($column)->get();
// use $comments in the template
}
}
default User model + simple Controller example; when getting the list of comments, just apply the orderBy() based on Input::get(). (be sure to do some input-checking ;) )
默认用户模型 + 简单控制器示例；获取评论列表时，只需应用基于 Input::get() 的 orderBy()。（一定要进行一些输入检查；））
回答by agm1984
I believe you can also do:
我相信你也可以这样做：
$sortDirection = 'desc';
$user->with(['comments' => function ($query) use ($sortDirection) {
$query->orderBy('column', $sortDirection);
}]);
That allows you to run arbitrary logic on each related comment record. You could have stuff in there like:
这允许您在每个相关评论记录上运行任意逻辑。你可以在里面放一些东西，比如：
$query->where('timestamp', '<', $someTime)->orderBy('timestamp', $sortDirection);
