在論壇索引頁面上將最新的評論主題置於頂端

Question

我正在構建一個論壇。每當用戶留下回復時，我都希望將發佈的主題置於頂端。對於沒有回覆的主題，我想通過created_at列來訂購它們。

你是怎麼做的？

論壇控制器

public function index() 
{ 
    $categories = Category::all(); 
    $topics = Topic::with(['comments' => function ($query) { 
    $query->orderBy('comments.created_at', 'desc'); 
    }])->paginate(20); 
} 

這是我演講的題目表

Schema::create('topics', function (Blueprint $table) { 
     $table->increments('id'); 
     $table->integer('category_id')->unsigned(); 
     $table->integer('user_id')->unsigned(); 

     $table->string('title'); 
     $table->text('body'); 
     $table->timestamps(); 
    }); 

這裏是我的評語表

$table->increments('id'); 
     $table->text('reply'); 
     $table->integer('user_id')->unsigned(); 


     $table->integer('topic_id')->unsigned(); 
     $table->foreign('topic_id')->refrenced('id')->on('topics')->onDelete('cascade'); 

     $table->timestamps(); 

評論模型

class Comment extends Model 
{ 
    protected $fillable = [ 
     'reply', 
     'user_id', 
     'topic_id' 
    ]; 


    public function topic() 
    { 
     return $this->belongsTo('App\Topic'); 
    } 

    public function user() 
    { 
     return $this->belongsTo('App\User'); 
    } 

} 

主題模型

class topic extends Model 
{ 
    protected $fillable = [ 
     'title', 
     'body', 
     'category_id' 
    ]; 

    public function category() 
    { 
     return $this->belongsTo('App\category'); 
    } 

    public function user() 
    { 
     return $this->belongsTo('App\User'); 
    } 

    public function comments() 
    { 
     return $this->hasMany('App\Comment'); 
    } 

} 

仍在試圖弄清楚這一點。任何幫助將非常感謝！

Answer 1

嘗試使用急於負載約束：

public function index() 
{ 
    $categories = Category::all(); 
    $topics = Topic::with(['comments' => function ($query) { 
     $query->orderBy('created_at', 'desc'); 
    }])->paginate(20); 

    return view('forums.index',compact('categories','topics')); 
} 

Answer 2

DB::table('topics') 
->leftjoin('comments', function($join) { 
        $join->on('topics.id', '=', 'comments.topic_id'); 
       }) 
->select(DB::raw('IF(comments.id IS NULL,0, 1) as topic_comment')) 
->orderBy('topic_comment', 'DESC') 
->orderBy('topics.created_at', 'DESC') 
->get(); 

the topic_comment as 1 records you can show on top right and rest wherever you want