I'm bulding a forum.
In the main page, I want to show the last reply for each forum.
The hierarchy is this:
forums
hasMany('App\\Topic')
hasManyThrough('App\\Topic', 'App\\Repley')
topics
belongsTo('App\\Forum')
hasMany('App\\Reply')
replies
belongsTo('App\\Topic')
I did this:
$forum->replies()->orderBy('created_at', 'desc')->first()
And it worked. But I want to sort by topics and replies. If I post new topic after the last reply, I want that show as the last reply.
Update : I did this, and it work. But is there any other way?
public function last() {
$topic = $this->topics->sortByDesc('created_at')->first();
$post = $this->replies->sortByDesc('created_at')->first();
return ($topic->created_at > $post->created_at) ? $topic : $post;
}
One solution I would suggest is to have the replied touch
the topics. https://laravel.com/docs/5.3/eloquent-relationships#touching-parent-timestamps
This way you can always order by the Topic's updated_at
because whenever a reply is created/edited it will update the Topic as well.
To achieve this you would just need to add:
protected $touches = ['topic'];
The above is assuming that the method name for the topics relationship in the replies model is topic()
.
Hope this helps!
You should have relationships between all of this models. Than you can simply:
$forum->topics->replies->sortByDesc('created_at')->first();
Read more about available methods for collections: https://www.laravel.com/docs/5.2/collections#available-methods
您可以尝试以下方法:
$forum->replies()->orderBy('id','DESC')->get();
您需要在orderBy子句中的主题和答复处写入原始表名。
$forum->topics->replies()->orderBy('topics.updated_at','DESC')->orderBy('repliese.updated_at','DESC')->first();
$latestReplay = Replay::orderBy('created_at','desc')->first();
$lastTopic = Topic::orderBy('created_at','desc')->first();
if ($latestReplay->created_at->gt($lastTopic->created_at)) {
echo $lastReplay->title." is the newer!!";
} else {
echo $lastTopic->title." is the newer!";
}
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