Rails Multiple Variables - ruby-on-rails

Question

I have multiple variables which I'm having issues lining up in a table. I have each grouping by year, but when the table is generated if there is only one results for one of the columns it puts it in the first row, instead of the corresponding year.
Here is an image of what it's doing. The Drylands column should be in the year 2006.
View
<% #all.zip(#irrigated, #semi, #dryland) do |a, b, c, d| %>
<tr>
<td><%= a.year %></td>
<td><% if a.nil? %>0<% else %><%= a.trial_id %><% end %></td>
<td><% if a.nil? %>0<% else %><%= "%.2f" % (a.lint/227) %><% end %></td>
<td><% if b.nil? %>0<% else %><%= b.trial_id %><% end %></td>
<td><% if b.nil? %>0<% else %><%= "%.2f" % (b.lint/227) %><% end %></td>
<td><% if c.nil? %>0<% else %><%= c.trial_id %><% end %></td>
<td><% if c.nil? %>0<% else %><%= "%.2f" % (c.lint/227) %><% end %></td>
<td><% if d.nil? %>0<% else %><%= d.trial_id %><% end %></td>
<td><% if d.nil? %>0<% else %><%= "%.2f" % (d.lint/227) %><% end %></td>
</tr>
<% end %>
Controller
#variety = Variety.where(variety_id: params[:variety_select]).group('variety_name')
#all = Result.where(variety_id: params[:variety_select]).group('results.year').where('results.lint > 0').select('AVG(results.lint) AS lint, results.year as year, COUNT(results.trial_id) AS trial_id').joins(:trial)
#irrigated = Result.where(variety_id: params[:variety_select]).group('results.year').where('results.lint > 0').select('AVG(results.lint) AS lint, results.year as year, COUNT(results.trial_id) AS trial_id').joins(:trial).where('trials.irrigated = ?', '1')
#dryland = Result.where(variety_id: params[:variety_select]).group('results.year').where('results.lint > 0').select('AVG(results.lint) AS lint, results.year as year, COUNT(results.trial_id) AS trial_id').joins(:trial).where('trials.irrigated = ?', '0')
#semi = Result.where(variety_id: params[:variety_select]).group('results.year').where('results.lint > 0').select('AVG(results.lint) AS lint, results.year as year, COUNT(results.trial_id) AS trial_id').joins(:trial).where('trials.irrigated = ?', '2')

Answer 1

I first would check what the queries actually return. Do you have records in Drylands for years 2004 and 2005? It doesn't seem so.
Maybe you can do this
a is never nil, otherwise a.year would crash, so no need for a.nil?
for the other values (b, c, d) you can check if !b.nil? and b.year == a.year ...
This should only print values in the respective year rows