Rails 3.2 Chartkick line chart grouped query doesn't display correctly

Question

I'm trying to use chartkick to display a multi series line chart which tracks total Inbound and Outbound Material flow by month over the past year.

The queries should generate something similar to this:

    SELECT SUM(ship_total_net_weight) AS sum_ship_total_net_weight,
    month(ship_date) AS month_ship_date, year(ship_date) 
    AS  year_ship_date 
    FROM [Downstream]
    WHERE is_active = 1 AND from_company_id = 89 
    AND
    (ship_date BETWEEN '2014-06-15 18:15:26.196' 
    AND '2015-06-15 18:15:26.196') 
    AND (to_company_id <> 89) 
    GROUP BY month(ship_date), year(ship_date)
    order By  year(ship_date), month(ship_date)

My chart kick code is as follows:

<%= line_chart [
              {name: "Inbound", data: Downstream.where(:to_company_id => current_user.company_id, :ship_date => 1.year.ago..Time.now).where('from_company_id <> ?', current_user.company_id ).group('month(ship_date), year(ship_date)').sum(:ship_total_net_weight)},
              {name: "Outbound", data: Downstream.where(:from_company_id => current_user.company_id, :ship_date => 1.year.ago..Time.now ).where('to_company_id <> ?', current_user.company_id ).group('month(ship_date), year(ship_date)').sum(:ship_total_net_weight)}
               ] %>

The result I get from chart kick is a line for each series with just two data points, one on Dec 31, 2013 and one on Dec 31, 2014.

Running the above SQL against the database generates 9 results ranging from 6/2014 to 2/2015

Why is the dataset different? Is my syntax wrong for chart kick? Do I need to change the query somehow?

Thanks for the help in advance!

Answer 1

I found the solution, my query was returning separate date/month columns so I needed to change the group clause, the following line chart works correctly:

<%= line_chart [
                {name: "Inbound", data: Downstream.where(:to_company_id => current_user.company_id, :ship_date => 1.year.ago..Time.now).where('from_company_id <> ?', current_user.company_id ).group('dateadd(month, datediff(month,1,ship_date),1)').sum(:ship_total_net_weight)},
                {name: "Outbound", data: Downstream.where(:from_company_id => current_user.company_id, :ship_date => 1.year.ago..Time.now ).where('to_company_id <> ?', current_user.company_id ).group('dateadd(month, datediff(month,1,ship_date),1)').sum(:ship_total_net_weight)}
                        ] %>

Using the dateadd and datediff functions in the group clause allows sorting by month/year of a date or date time field and returns the full date in a single column.

-Side note - I'm using SQLServer which is not supported by the groupdate gem that's often used on conjunction with chartkick.