Laravel计数Eloquent属于ToMany相关模型

Question

I'm new to Laravel, and I got stuck with the following issue: I have a table for the users, and groups, and a table for connecting them. The general task any user can join any group.

----------------------------------------------
| users        | groups     | user_groups    |
|--------------------------------------------|
| id - int pk  | id - pk    | id - pk        |
| name text    | name       | user_id - fk   |
| email        |            | group_id - fk  |
| phone        |            | any_attr       |
----------------------------------------------

I have the following models:

class User
{
    ...
    public function groups()
    {
        return $this->belongsToMany(Group::class, 'user_groups')->withPivot(['is_notification_requested']);
    }
    ...
}


class Group
{
    ...
    public function users()
    {
        return $this->belongsToMany(User::class, 'user_groups');
    }
    ...
}

How do I get all of the groups, with a count of the members? I need the Group model, and a count of the users in the group.

Answer 1

If you're using Laravel 5.3, you can simply add withCount('relationship') as documented here: https://laravel.com/docs/5.3/eloquent-relationships#counting-related-models

Here's an example following your code:

$groups = Group::withCount('users')->get();

Now you can do this:

foreach($groups as $group) {
    echo $group->user_count
}