code.rb

#course_helper
 def coursenames(courseid)
  @coursedept = Department.all(:include => :courses, :conditions => ["courses.id = ?",courseid]) 
   for i in @coursedept
     return i.name #return the department's name
    end             
 end
 
 
  <% @course.each do |course| %> 
   <tr>
     <td><%= course.code %></td>
     <td><%= course.name %></td>
     <td><%= coursenames(course.id) %>
     </td> ...
 
#Assuming a course belongs to more than one Department,this only shows the first Department the course belongs to.
#How do i please get the rest as a comma seperated list