如何获得评论帖子的所有用户？

I'm working with Laravel 5 and I've the following Models

PostComment.php

class PostComment extends Model
{
    protected $fillable = [
        'post_group_id', 'user_id', 'comment_content'
    ];

    public function post(){
        return $this->belongsTo('App\PostGroup');
    }

    public function user(){
        return $this->belongsTo('App\User');
    }

}

PostGroup.php

class PostGroup extends Model
{
    protected $fillable = [
        'group_id', 'user_id', 'post_content'
    ];

    public function user(){
        return $this->belongsTo('App\User');
    }

    public function group(){
        return $this->belongsTo('App\Group');
    }

    public function commented(){
        return $this->hasMany(
            'App\PostComment'
        );
    }
}

Group.php

class Group extends Model
{

    protected $fillable = ([
    'id'
    ]);

    public function users(){
        return $this->belongsToMany(
            'App\User',
            'user_group'
        );
    }

    public function members(){
        return $this->belongsToMany(
           'App\User',
           'user_group'
        )->wherePivot('state','accepted');
    }


    public function posted(){
        return $this->hasMany(
            'App\PostGroup'
        );
    }
}

My web application presents groups, in which you can create posts and in which post you can write comments. In my database I've the following relationships:

• Group: (id, name, description);
• PostGroup: (id, group_id, user_id, post_content);
• PostComment: (id, post_group_id, user_id, comment_content);

What I want to do is to create a collection of User objects, and then make a query to get all users, subscribed to a group, who have commented on a certain post, in MySQL looks like:

select users.* from users, post_comments where users.id = post_comments.user_id and post_comments.post_group_id="1"

So in my controller I've the following code

$theGroup = Group::find($groupId);
$thePost = PostGroup::find($postId);
$memberList = User::where('id', '<>', Auth::user()->id)->whereIn('id', $theGroup->users->pluck('id'))->

So, what I want to do is to extend that query to get the desidered result with ->get()->sortBy('last_name');, how can I exted it after the whereIn?

EDIT

User.php

class User extends Authenticatable
{

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'name', 'email', 'password',
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password', 'remember_token','created_at','updated_at'
    ];

    public function groups(){
        return $this->belongsToMany('App\Group','user_group');
    }

    public function groupsAsAdmin(){
        return $this->belongsToMany('App\Group','user_group')->wherePivot('role','admin');
    }

    public function groupsAsMember(){
        return $this->belongsToMany('App\Group','user_group')->wherePivot('state','accepted');
    }

    public function groupsAsInvited(){
        return $this->belongsToMany('App\Group','user_group')->wherePivot('state','pending');
    }

    public function posted(){
        return $this->hasMany('App\PostGroup');
    }

    public function commented(){
        return $this->hasMany('App\PostComment');
    }
}

From your description, you already come up with a list of Users in advance, so that you only will find Posts with a Comment of these specific users.

Basically, what you want is to use whereHas($relation, $calback) to perform the checks you described:

$userIds = [2, 3, 5, 7, 11, 13, 17]; // or query them...
$postId = 123; // the id of the post where we want to look through the comments

User::where('id', '<>', Auth::id())
    ->whereIn('id', $userIds)
    ->whereHas('comments', function ($query) use ($postId) {
        $query->where('post_group_id', $postId);
    })
    ->get();

This will simply check if a user has written a Comment for the given post. Because you forgot to post your User model, I assumed that there is a relation available for the comments of the user.

You could also combine the first two conditions (user in list, but not the authenticated one) into one, if you want. $userIds = array_diff($userId, [Auth::id()]) does the job. where('id', '<>', Auth::id()) can be dropped from the query then.

If you do also need to check for an active subscription of the user to a group, it will be slightly more complex. But as you commented, you are already finding only users for a group, so this should be fine.

In PostComment, try this

$this->selectRaw(‘user_id, comment_content’)->where(‘post_group_id’, 1)->groupBy(‘user_id’)->get();