Best way in MySQL or Rails to get AVG per day within a specific date range

Question

I\'m trying to make a graph in Rails, for example the avg sales amount per day for each day in a given date range

Say I have a products_sold model which has a \"sales_pr

Answer 1

To dry up a bit:

ave_prices = Merchant.find(1).products.average(:sales_price, :group => "DATE(created_at)")
date_aves = (from_date..to_date).map{|dt| [dt, ave_prices[dt.strftime "%Y-%m-%d"] || 0]}