<table>
  <thead>
    <tr style="border-bottom: 2px solid black;">
      <th> <%= sortable "scode", "School" %></th>
    </tr>
  </thead>

  <tbody>
    <% @dprojects.where.not(status: "Completed").each do |dproject| %>
      <tr>
        <td width="20%" class="dotted"><%= dproject.school.dname[0,25] + "..." %></td>
      </tr>
    <% end %>
  </tbody>
</table>

class Dproject < ActiveRecord::Base
    belongs_to :school, foreign_key: 'scode'
end

def index
    @dprojects = Dproject.order(params[:sort])
    respond_with(@dprojects)
end

module DprojectsHelper
    def sortable(column, title = nil)
        title ||= column.titleize
        link_to title, :sort => column
    end
end

<th> <%= sortable "dproject.school.dname", "School" %></th>