title: Rails Active Record `group`: Why does this return only a few columns?
body: <p>I have this from a select statement in my Rails app:</p>
  
  <pre><code>...
   #&lt;DailyStat subject: "Macroeconomics", topic: "Overview Of Economics", item_count: 160, correct_item_count: 0&gt;,
   #&lt;DailyStat subject: "Macroeconomics", topic: "Overview Of Economics", item_count: 1, correct_item_count: 0&gt;,
   #&lt;DailyStat subject: "Macroeconomics", topic: "Unemployment", item_count: 1, correct_item_count: 0&gt;,
   #&lt;DailyStat subject: "Macroeconomics", topic: "Inflation", item_count: 2, correct_item_count: 0&gt;,...
  </code></pre>
  
  <p>I get this when I do a basic select of these columns. Now my problem is, when I do <code>daily_stats.select("subject, topic, sum(correct_item_count), sum(item_count)").group(:topic)</code> to aggregate the columns as to combine the item_counts and the correct_item_counts, the resultant result set is:</p>
  
  <pre><code>#&lt;DailyStat topic: "Demand And Consumer Behavior"&gt;, #&lt;DailyStat topic: "Obligations"&gt;, #&lt;DailyStat topic: "Computerized Auditing"&gt;, #&lt;DailyStat topic: "Inflation"&gt;, #&lt;DailyStat topic: "Overview Of Economics"&gt;
  </code></pre>
  
  <p>I lose the counts. This must be just some sort of syntax issue, but I'm having trouble. How do I get the counts to add up?</p>