Counting and grouping at the same time

Question

I have a Mail model with the following schema:

t.string   \"mail\"
t.integer  \"country\"
t.boolean  \"validated\"
t.datetime \"created_at\"
t.d         


        

Answer 1

With Rails 3 you can simplify it further:

Mail.where(validated: true).count(group: :country)

You can order by fields in the group - in this case only :country would be valid:

Mail.where(validated: true)
    .order(:country)
    .count(group: :country)

You can also order by the count, using "count_all":

Mail.where(validated: true)
    .order("count_all desc")
    .count(group: :country)

You can also limit the number of groups returned. To do this you must call limit before calling count (because #count returns ActiveSupport::OrderedHash):

Mail.where(validated: true)
    .order("count_all desc")
    .limit(5)
    .count(group: :country)

Updated syntax for Rails 4:

Mail.where(validated: true)
    .group(:country)
    .count