related models count

What is is the desired way to call ‘count’ on a collection?

Say i have a model

User = db.Model.extend({
  tableName: 'users',
  photos: function(){ return this.hasMany(Photo); }
});

new User({id: 1}).fetch().then(function(user) {
  user.photos().count().then(...)  // <- seems to be a good way to query 'select count(*) from photos where user_id = ?'
});

[chrisfrancis27]

Is there a recommended standard way of achieving this yet? I’ve tried this on my Dataset model:

commentCount: function() {
  return this.hasMany('Comment').query({
    count: 'id as comment_count'
  });
},
comments: function() {
  // One-to-many
  return this.hasMany('Comment');
}

Basically I want a comments array attribute to be populated when retrieving a single model, but a commentCount for each model when retrieving a collection. This seems to generate the right sort of query:

select count("id") as "comment_count" from "comments" where "comments"."dataset_id" in (?, ?, ?)

But the response is returning "commentCount": [] (an empty array, not a number as I’d expect). Any ideas where I’m going wrong?

Cheers

[frogcjn]

    User.collection().query(function (qb) {
      qb.join('courses', 'users.id', 'courses.user_id');
      qb.groupBy('users.id');
      qb.select("users.*");
      qb.count('* as course_count');
      qb.orderBy("course_count", "desc");
    })