title: Join and select multiple column
body: <p>I'm trying to select multiple columns after doing a join. I couldn't find a way to do so using ActiveRecord without writing SQL between quotation marks in the query (Thing I'd like to avoid)</p>
  
  <p>Exploring Arel, I've found I could select multiple columns using "project", however I'm not quite sure if I should use Arel directly or if there was a way to achieve the same with AR.</p>
  
  <p>These is the code in Arel:</p>
  
  <pre><code>l = Location.arel_table
  r = Region.arel_table
  
  postcode_name_with_region_code = l.where(l[:id].eq(location_id)).join(r).on(l[:region_id].eq(r[:id])).project(l[:postcode_name], r[:code])
  </code></pre>
  
  <p>After running this query I'd like to return something along the lines of:
  (<em>Pseudo-code</em>)</p>
  
  <pre><code>"#{:postcode_name}, #{:code}"
  </code></pre>
  
  <ol>
  <li>Is there a way to achieve the same query using AR?</li>
  <li>If I stick to Arel, how can I get the values out of the SelectManager class the above query returns.</li>
  </ol>
  
  <p>Thanks in advance,</p>