<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Comment extends Model
{
 /**
  * 要更新的所有關聯(lián)表
  *
  * @var array
  */
 protected $touches = ['post'];

 /**
  * Get the post that the comment belongs to.
  */
 public function post()
 {
  return $this->belongsTo('App\Post');
 }
}

$posts = App\Post::with('comment:id,name')->get();

return redirect()->action('SomeController@method', ['param' => $value]);

...
public function post()
{
 return $this->belongsTo(App\Post::class)->withDefault();
}

@foreach ($users as $user)  
 @foreach ($user->posts as $post)   
 @if ($loop->parent->first)    
  This is first iteration of the parent loop.   
 @endif  
 @endforeach 
@endforeach

Route::get('/mailable', function () {
 $invoice = App\Invoice::find(1);
 return new App\Mail\InvoicePaid($invoice);
});

$posts = Post::has('comment', '>', 5)->get();

$posts = Post::withTrashed()->get();

$posts = Post::onlyTrashed()->get();

Post::withTrashed()->restore();

$posts = Post::whereDate('created_at', '2018-01-31')->get(); 
$posts = Post::whereMonth('created_at', '12')->get(); 
$posts = Post::whereDay('created_at', '31')->get(); 
$posts = Post::whereYear('created_at', date('Y'))->get(); 
$posts = Post::whereTime('created_at', '=', '14:13:58')->get();