在视图中创建 Ruby on Rails 矩阵表

Question

I have records with the fields "year" and "month" and "value". What I'd like to do is to create a 12 column table corresponding with each "month" that displays the "value" in the "year" row. It seems like a pretty straightforward table to construct but I can't seem to get the view to display it properly.

I won't bother posting the code (yet) that I came up with already because nothing seems close to getting what I'm looking for. I seems like this might be a pretty common thing to do with "group_by" but I have yet to see this type of example online.

here is the table details:

create_table "returns", force: true do |t| 
  t.integer "year" 
  t.integer "month" 
  t.decimal "value" 
end

What is the best route to go about doing this?

Answer 1

Here is an example how you can do it, this is not efficient way to do it but it is something you can improve:

years = (2008..2015).to_a
months = (1..12).to_a

<table>
<tr>
    <td>Januray</td>
    ## .. rest of <td>'s of the month name
</td>
    years.each do |year|
      <tr>
        <td><%=year%></td>
        months.each do |month|
          <td><%= Return.where(year: year,month: month).first.try(:value) %></td>
        end
      </tr>
    end
</table>