How to join three table by laravel eloquent model

Try:

$articles = DB::table('articles')
            ->select('articles.id as articles_id', ..... )
            ->join('categories', 'articles.categories_id', '=', 'categories.id')
            ->join('users', 'articles.user_id', '=', 'user.id')

            ->get();

$articles =DB::table('articles')
                ->join('categories','articles.id', '=', 'categories.id')
                ->join('user', 'articles.user_id', '=', 'user.id')
                ->select('articles.id','articles.title','articles.body','user.user_name', 'categories.category_name')
                ->get();
return view('myarticlesview',['articles'=>$articles]);

With Eloquent it's very easy to retrieve relational data. Check out the following example with your scenario in Laravel 5.

We have three models:

1. Article (belongs to user and category)

2. Category (has many articles)

3. User (has many articles)

---

1. Article.php

    <?php
    namespace App\Models;
    use Eloquent;
    
    class Article extends Eloquent {
        protected $table = 'articles';
    
        public function user() {
            return $this->belongsTo('App\Models\User');
        }
    
        public function category() {
            return $this->belongsTo('App\Models\Category');
        }
    }

2. Category.php

    <?php
    namespace App\Models;
    
    use Eloquent;
    
    class Category extends Eloquent {
        protected $table = "categories";
    
        public function articles() {
            return $this->hasMany('App\Models\Article');
        }
    }

3. User.php

    <?php
    namespace App\Models;
    use Eloquent;
    
    class User extends Eloquent {
        protected $table = 'users';
    
        public function articles() {
            return $this->hasMany('App\Models\Article');
        }
    }

You need to understand your database relation and setup in models. The user has many articles. The category has many articles. Articles belong to user and category. Once you set up the relationships in Laravel, it becomes easy to retrieve the related information.

For example, if you want to retrieve an article by using the user and category, you would need to write:

$article = \App\Models\Article::with(['user','category'])->first();

and you can use this like so:

//retrieve user name 
$article->user->user_name  

//retrieve category name 
$article->category->category_name

In another case, you might need to retrieve all the articles within a category or retrieve all of a specific user`s articles. You can write it like this:

$categories = \App\Models\Category::with('articles')->get();
$users = \App\Models\Category::with('users')->get();

You can learn more at http://laravel.com/docs/5.0/eloquent