Calling .values.sum might have to load a LOT of (id, count) rows so it isn't a
very scalable solution.
Calling regroup or something is actually changing what would be counted - the
group can affect the count, especially if you use HAVING clauses.
There's nothing wrong with having the grouped count functionality, but it's
messing up the #count API IMHO.
On 13/09/2014, at 03:40 , Gabriel Sobrinho <gabriel.sobri...@gmail.com> wrote:
> I'm against to count and size works equally since I would want to know how
> many grouped records do I have (i.e.: how many roles do I have on determining
> relation).
>
> I think that count and size is working as both should.
>
>
> Although, if you want to count all records of a grouped relation, you have to
> remove the group or just sum the counts:
>
> User.count
>
> or:
>
> User.group(:role).count.values.sum
>
> Not elegant but if you can't remove the group for that count, you have to do
> that.
>
>
> One possible option would rails have something like regroup(false) as
> reorder(false), but again I think that just adding the values is more easier
> for everyone :)
>
> On Thursday, September 11, 2014 11:54:14 PM UTC-3, Shinohara Teruki wrote:
> >> size in this case is an pretty much an "alias" for count, thus it's gonna
> >> work the same way as count when grouping.
>
> I think that current #size don't behave like an alias for #count.
>
> g = User.group(:role); g.load; g.count
> => {:normal=>3, :admin=>4}
>
> g = User.group(:role); g.load; g.size
> => 2
>
> When I call #load before #count or #size, a return value of #count don't
> equals to a return value of #size.
>
>
> >> Is there any particular reason to know how many records returned if you
> >> are grouping?
>
> I expect #count and #size to return same value.
> It is not the case that I want to know how many records the grouping query
> returns.
>
> My ideal implementation:
>
> g = User.group(:role); g.load; g.count
> => {:normal=>3, :admin=>4}
>
> g = User.group(:role); g.load; g.size
> =>{:normal=>3, :admin=>4}
>
> or
>
> g = User.group(:role); g.load; g.count
> => 2
>
> g = User.group(:role); g.load; g.size
> =>2
>
> What do you think?
>
> Thank you
>
>
> 2014年9月12日金曜日 8時21分39秒 UTC+9 Carlos Antonio da Silva:
> size in this case is an pretty much an "alias" for count, thus it's gonna
> work the same way as count when grouping.
>
> Is there any particular reason to know how many records returned if you are
> grouping?
>
> On Wed, Sep 10, 2014 at 11:16 AM, Shinohara Teruki <ts....@gmail.com> wrote:
> ActiveRecord::Relation.size returns a Hash when I use a group method.
> I think that a size method is expected to return integer typically.
>
> I propose this implementation:
>
> def size
> if loaded?
> @records.length
> else
> count_value = count(:all)
> count_value.is_a?(Hash) ? count_value.length : count_value
> end
> end
>
> This is a current implementation:
>
> #
> https://github.com/rails/rails/blob/master/activerecord/lib/active_record/relation.rb
> # Returns size of the records.
> def size
> loaded? ? @records.length : count(:all)
> end
>
>
> A count method is implemented on calculations.rb.
> https://github.com/rails/rails/blob/master/activerecord/lib/active_record/relation/calculations.rb
>
>
> What do you think?
>
> Thank you
>
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> At.
> Carlos Antonio
>
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