Query with attributes from related model

I have a Post model that can have multiple categories:

The relationship looks like this:

public function categories()
    {
        return $this->hasMany('App\PostsCategories', 'post_id', 'id');
    }

PostsCategories table contains IDs of posts and their categories.

I'm trying to query posts by multiple criteria (post name, category, etc.) like this:

public function search(Request $request)
{   
    $post_name= $request->post_name;
    $category_id= $request->category_id; // value is integer 1- 20

    $posts= Post::query()
            ->where('post_name', 'LIKE', "%{$post_name}%")
            // and where category equals $category_id
            ->paginate(50);
}

I'm having trouble with figuring out how to add category to my query. How can I include attributes form related models in my query?

MichalOravec

6 years ago

Best Answer

Level 75

@mleontenko

$posts = Post::where('post_name', 'LIKE', "%{$post_name}%")->whereHas('categories', function($query) use ($category_id) {
    $query->where('id', $category_id);
})->paginate(50);

Documenation: https://laravel.com/docs/7.x/eloquent-relationships#querying-relationship-existence

But I think that your logic is wrong.

Post belongs to Category, so post should have a category_id

Another things are Tags, Post could have many Tags, and Tags could have many posts.

In that case it's many to many relationships.

But that code above will work.

1 like

Rayray

6 years ago

Level 1

if i were you i would do something like this

posts model

use App\Postcategory;

public function postcategories() { return $this->hasMany(PostsCategory::class); }

this means you have a single post that has multiple categories

Then to access all the post categories in a post

you can state like $posts = Post::all(); foreach($posts as $post){ foreach($post->postcategories as $postcat){ $postcat->title } //this will give you a title of the category

}

i guess you want to foreach all posts that has that category.

Am also stuck now.....

1 like

mleontenko

6 years ago

Level 2

@michaloravec Thanks, that will work!

I used Post - Category analogy only for example, my app has entirely different classes that would be harder to explain. It's true this logic would be wrong in Posts and Categories case...

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