我正在建立一个论坛。每当用户留下回复时，我想将已发布的主题放在首位。对于没有回复的主题，我想按created_at列排序。
你是怎么做到的？
论坛控制器
public function index()
{
$categories = Category::all();
$topics = Topic::with(['comments' => function ($query) {
$query->orderBy('comments.created_at', 'desc');
}])->paginate(20);
}
这是我的主题表
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();
});
这是我的评论表
$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();
注释模型
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');
}
}
主题模型
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');
}
}
仍在努力解决这个问题。 任何帮助将不胜感激！
尝试使用带有约束的预先负载：
public function index()
{
$categories = Category::all();
$topics = Topic::with(['comments' => function ($query) {
$query->orderBy('created_at', 'desc');
}])->paginate(20);
return view('forums.index',compact('categories','topics'));
}
DB::table('topics')
->leftjoin('comments', function($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