从关联的 model 获取最大/最小日期值

Question

Rails 2.3.5

Below, (tickets:have_many => logs), I'm just listing the 'created_at' value of index 0. What I'd like to get is the max & min values for that field (saying something like 'first log was 07-01-2011, last log entry 07-18-2011')

<% @tickets.each do |t| %>    
    <% if  !t.log_entries[0].nil? %>
       <%= t.log_entries[0].created_at %>
       <% end %>
    <% end %>
<% end %>

Is there an easy way to do this? I tried playing around with Max but couldn't figure out a working syntax. The only other thing I can thing of is to do a find_first asc & desc query in the view.

Thanks !

Answer 1

You can easily do this by a Rails subquery :

 From <%= @ticket.log_entries.find(:first, :order => "created_at ASC").created_at.to_s %>
 to <%= @ticket.log_entries.find(:first, :order => "created_at DESC").created_at.to_s %>

Happy coding:)