Group by with counts

[Ryan Yuan]

Hi all,

I have the following data columns in my table:

occurred_at, name
2012-01-01, Ryan
2012-01-01, Ryan
2012-01-01, Mark
2012-01-01, Ryan
2012-01-01, Paul
2012-01-01, John
2012-02-01, Ryan
2012-02-01, Mark
2012-02-01, Ryan
2012-02-01, Mark
2012-02-01, Paul
2012-02-01, Kevin
2012-03-01, Ryan
2012-03-01, Gary
2012-03-01, Ryan
2012-03-01, Mark
2012-03-01, Paul
2012-03-01, Kevin

What I'm trying to do is Group the names by date and add a count and
output this to a json

{ date: 2012-01-01, ryan: 3, mark: 1, paul: 1, john: 1 }

I have the following code so far:

# user controller
def index
@users = User.show_data
render :json
end

# user model

def self.show_data(start = 14.months.ago)
total_users = users_by_month(start)
(start.to_date..Date.today).map do |date|
{
occurred_at: date,
total_users[date].name.to_sym: total_users[count],
}
end
end

def self.users_by_month(start)
users = where(occurred_at: start.beginning_of_day..Time.zone.now )
users = users.group("date(occurred_at)")
users = orders.select("occurred_at, count(name) as user_name")
users.each_with_object({}) do |user, names|
names[user.occurred_at.to_date] = user.user_name
end
end

Thanks in advance,

Ryan

--
Posted via http://www.ruby-forum.com/.

[Frederick Cheung]

On Monday, February 25, 2013 5:49:56 PM UTC, Ruby-Forum.com User wrote:

def self.users_by_month(start)
    users = where(occurred_at: start.beginning_of_day..Time.zone.now )
    users = users.group("date(occurred_at)")
    users = orders.select("occurred_at, count(name) as user_name")
    users.each_with_object({}) do |user, names|
       names[user.occurred_at.to_date] = user.user_name
    end
  end

I think you're overcomplicating a little - if you do User.where(....).group('date(occurred_at), name').count then you should get back a hash of where the keys are [date,name] pairs and the values are the counts

 

Fred