Mongoid or/any_of unexpected behaviour - ruby-on-rails

Question

I'm having an issue with mongoid any_of. I'm trying to find objects that have either one field > 0, or another one > 0. My query is :
Model.any_of(best_friend_method.gt => 0, method.gt => 0).desc(best_friend_method, method)
It is "translated" in :
#<Mongoid::Criteria
selector: {"$or"=>[{:best_friends_lc_sum=>{"$gt"=>0}, :lc_sum=>{"$gt"=>0}}]},
options: {:sort=>[[:best_friends_lc_sum, :desc], [:lc_sum, :desc]]},
class: FbAlbum,
embedded: false>
As I understand it, this is what I want. But it only returns me 6 results. Model.where(:best_friends_lc_sum.gt => 0).count returns me 6 results too, but Model.where(:lc_sum.gt => 0).count returns me ~850 objects.
I expect my query to return the union of those two : is a mongoid/mongodb error, or am I doing something wrong ?
FYI : mongoid 2.4.5, mongodb 2.0.2, rails 3.1.3
Thanks for your time!

Answer 1

It's because you pass only one args and not 2 args. So it's like you have no $or usage.
Try :
Model.any_of({best_friend_method.gt => 0}, {method.gt => 0}).desc(best_friend_method, method)
In this case the Criteria become :
#<Mongoid::Criteria
selector: {"$or"=>[{:best_friends_lc_sum=>{"$gt"=>0}}, {:lc_sum=>{"$gt"=>0}}]},
options: {:sort=>[[:best_friends_lc_sum, :desc], [:lc_sum, :desc]]},
class: FbAlbum,
embedded: false>
Sometime the usage of {} is mandatory to separate different hash.

Answer 2

In case this helps someone...In Mongoid 3, the Origin gem provides the syntax for querying. Here is the list of methods that you can use to write your Mongoid 3 queries. Among those methods is the or method which allows you to perform an $or query:
# Mongoid query:
Model.or(
{ name: "Martin" }, { name: "Dave" }
)
# resulting MongoDB query:
{
"$or" => [
{ "name" => "Martin" }, { "name" => "Dave" }
]
}
Using the OP's original example, it can be rewritten as:
Model.or(
{ best_friend_method.gt => 0 },
{ method.gt => 0 }
).order_by(
best_friend_method,
method
)
At least one of the hashes passed to the or method must match in order for a record to be returned.