Question

有两种型号：分类和邮政。

class Category extends Model
{

    public function posts()
    {
        return $this->hasMany('App\Post','category_id');
    }
}

class Post extends Model
{   
    public function category()
    {
        return $this->belongsTo('App\Category');
    }
}
//Get data
      $data = Category::with(['posts' => function($query){
            $query->orderBy('id','desc')->first();
          }])->get();

在这种情况下，将显示所有类别，并且只显示一个帖子。我需要从每个类别中获得一个记录帖子。

示例：
第1类 - Post1
第2类 - 第2栏第3类 - Post5
第4类 - 邮政15
一个类别 - 最后一个类别。

Answer 1

您有Post个// Category.php class Category extends Model { // This gets ALL posts public function posts() { return $this->hasMany('App\Post','category_id'); } // This gets the most recent post // I am ordering by created_at instead of ID, but you can use ID // if it makes sense for your application) public function mostRecentPost() { return $this->hasOne('App\Post','category_id') // hasOne is the key here ->orderBy('created_at', 'DESC'); } }个，但您只想获取最新帖子，以便添加其他关系。

$data = Category::with('mostRecentPost')->get();

然后当你想要使用它时......

      final OkHttpClient okHttpClient = new OkHttpClient.Builder()
            .readTimeout(60, TimeUnit.SECONDS)
            .addInterceptor(new Interceptor() {
                @Override
                public okhttp3.Response intercept(Chain chain) throws IOException {
                    Request.Builder ongoing = chain.request().newBuilder();
                    ongoing.addHeader("Cache-Control", "no-cache");
                    ongoing.addHeader("User-Agent", System.getProperty("http.agent"));
                    return chain.proceed(ongoing.build());
                }
            })
            .connectTimeout(100, TimeUnit.SECONDS)
            .build();
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(globalUrl())
                .addConverterFactory(GsonConverterFactory.create())
                .client(okHttpClient)
                .build();

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