'Laravel: Select first record in a One-to-Many relation

Is it possible to use eloquent to retrieve just the first match in a one to many relationship?

What do I mean, well, let me explain.

Most of us are familiar with the common one to many relationship of (or between) posts and comments, as in:

  • A post has can have zero or more comments
  • A comment belongs to one post

Which is represented in laravel as:

class Post extends Model
{
    public function comments()
    {
        return $this->hasMany(Comment::class);
    }
}

class Comment extends Model
{
    public function post()
    {
        return $this->belongsTo(Post::class);
    }
}

So I wanted to find out if it is possible to retrieve post(s) with just the first comment in the result and not all comments that belong to the post(s).

$posts = Post::with('comments.0')->get(); 
$post = Post::with('comments.0')->first();

With comments.0, as my way of saying, get just the first comment belonging to the each or that post.

I have looked at this question and I was wondering how it could be done using eloquent?

Thank you.

laraveleloquentone-to-many


Solution 1:[1]

Problem:

To get 1 Comment per Post you will have to limit the subquery. I would do it like that:

Solution:

Post::with(['comments' => function ($query){
    return $query->first();
}])->get();

With that, we are returing the first() comment and get() all posts do do so for.

Solution 2:[2]

$post = Post::leftJoin('comments as c','c.post_id','=','posts.id')->select('posts.id','posts.title','c.id as comment_id','c.description')->groupBy('posts.id')->get();

This query return only one comment if exist otherwise return null data which is selected from comments table. I added some dummy fields in select you can add which required.

Solution 3:[3]

If you need to use one of the comments, you could simply access it like this

$posts = Post::with('comments')->get();
foreach($posts as $post){
   // To get the first comment out of the $post->comment collection
   $post->comments->first();
}

Where first is a collection method. https://laravel.com/docs/7.x/collections#method-first

The number of queries would be two for this case when you eager load all the comments. And even if there's a way to eager load one comment in Eloquent, then too there would be minimum of two queries required.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1
Solution 2 Niyanta Bhayani
Solution 3 Aashish gaba

Related Questions