多对多关系查询。 拉拉韦尔

Question

I'm trying to figure out how I can do a query within a query. (if that even makes sense) I want to grab all the activities. For each activity I want to get the count of users that did the activity. Then I want to order all the activities in DESC order based on the amount of users that did each activity. I'm basically making a "Popular Activities Page" where I show the all activities starting with the activity done by the most users.

I have 3 main tables for this

users

| id | name | password | email | created_at |

activities

| id | title | description | created_at |

resource This is a table I'm using for posts which shows which user did which activity. (Users can show what activities they did, and attach media and locations to the post)

| id | user_id | activity_id | media_id | location_id | created_at |

Here are my models for each table

User Model

class User extends Eloquent {

    protected $table = 'users';

    /**
     * get the activities associated with the given user
     * @return mixed
     */
    public function activities()
    {
        return $this->belongsToMany('Acme\Activities\Activity', 'resource', 'activity_id');
    }

    public function posts(){
        return $this->hasMany('Acme\Resource\Resource');
    }

    public function media()
    {
        return $this->hasMany('Acme\Media\Media');
    }

    public function locations()
    {
        return $this->hasMany('Acme\Locations\Location');
    }
}

Activity Model

class Activity extends Eloquent  {

    protected $table = 'activities';


    public function posts(){
        return $this->hasMany('Acme\Resource\Resource', 'resource_id');
    }

    /**
     * get the users associated with the given activity card
     * @return mixed
     */
    public function users()
    {
        return $this->belongsToMany('Acme\Users\User', 'resource', 'user_id');
    }

}

Resource Model

class Resource extends Eloquent {

    protected $table = 'resource';


    public function user()
    {
        return $this->belongsTo('Acme\Users\User', 'user_id');
    }

    public function activities()
    {
        return $this->belongsTo('Acme\Activities\Activity', 'activity_id');
    }

    public function media()
    {
        return $this->hasMany('Acme\Media\Media', 'media_id');
    }

    public function locations()
    {
        return $this->belongsTo('Acme\Locations\Location', 'location_id');
    }
}

I know I can get all activities using

Activity::get()

I can get a user count for a specific activity using

User::whereHas('resource', function($q) use ($activity_id){
    $q->where('activity_id', $activity_id);
})->get()->count();

but I don't know how I can put all of this together in order to get all Activities sorted by user count, starting with the activity with the highest user count.

How would I make this query using eloquent?

Thanks in advance!

Answer 1

try

Resource::select(DB::raw('*, COUNT(distinct(user_id)) as user_count'))->group_by('activity_id')->order_by('user_count', 'desc')->get();

You could then do this

$results = Resource::select(DB::raw('*, COUNT(distinct(user_id)) as user_count'))->group_by('activity_id')->order_by('user_count', 'desc')->get();

foreach ($results as $result) {
    $activity = Activity::where('id','=',$result->activity_id)->first();
    // do stuff to display data for this activity like
    // $activity->title or $activity->description
    $count = $result->user_count; 
}