ruby - Rails loop through ActiveRecord::Associations:CollectionProxy -

i've got activerecord::associations:collectionproxy of format

#<dailyviewmetric article_id: xxxxxx, date: xxxxxxx, views: xxxxxx, visitors xxxxx,.....> in variable called metrics.

the article_id foreign key , repeated in table (as 1 article can have metrics on consecutive days (i.e. 15 views today , 20 day after).

i need way loop through , apply different operations of these metrics smallesest date each article, total number of views (= sum(views)). tried metrics.map |a| , metrics.collect ruby errors undefined method 'views' example let's go following simplified dataset

article_id date         views 1          2014-01-01   10 2          2014-01-01   15 1          2014-01-02   20 2          2014-01-02   12 3          2014-01-02   6 

should result in following new array afterwards:

article_id date         views 1          2014-01-01   30 2          2014-01-01   27 3          2014-01-02   6 

as can see views variable holds sum of views respective article, date variable minimum of dates. how do properly? tried metrics.to_a still error.

edit

i tried dailyviewmetric.find_by_sql("select article_id, sum(views) daily_view_metrics article_id in(select id articles user_id=xxx) group article_id")

which, if execute query in mysql console, works fine , returns second table above. when run in rails console gives me

[#<dailyviewmetric id: nil, article_id: 1089536>, #<dailyviewmetric id: nil, article_id: 1128849>, #<dailyviewmetric id: nil, article_id: 1141623>, 

you can in sql/activerecord. query want run is

select article_id, min(date), sum(views)   daily_value_metrics -- or whatever table called group article_id 

you can run activerecord following:

table = dailyvaluemetric.arel_table results = dailyvaluemetric.select(table[:article_id],    table[:date].minimum.as('date'),    table[:views].sum.as('views')).group(:article_id).to_a # calling to_a can call first example results.first.date #=> date results.first.views #=> views results.first.article_id #=> id 

the records

[#<dailyviewmetric id: nil, article_id: 1089536>, ...] 

because sql query not return id column in result set. because of way activerecord::base#inspect shows columns defined on table, , not returned values outside of table columns. views , date not shown, unless there column same name, if call attributes on model instance, able value