I have three models: Amod, Bmod and Cmod.

Amod has_many Bmods, Bmod has_many Cmods.

Modb has a column called “integer” (type: integer) and Modc has a column called “date” (type: date).

I am using Chartkick to chart my data, which takes an hash (or array) as an argument.

What I am trying to do is:

• For a given record in Amod, return a hash where the keys are made up of each distinct ‘date’, and the values are made up of the the ‘integers’ that have that date.
• I would like to generate three variants of this hash: one that shows the sum of all integers with a given date, one that shows the mean of all integers with a given date, and one that shows the total number of integers with a given date.

Here is what I have:

  mybmod = Bmod.where(amod_id: Amod.first.id) # Seems to work fine
  myjoin = mybmod.joins(:cmods).select("cmods.date, bmods.integer") # Seems to work fine
  mygroup = myjoin.group(:date) # Seems to work fine
  myhash = mygroup.sum # Returns all values as 0
  myhash = mygroup.count # Returns an error

Any ideas where I am going wrong here?