title: group by is not working in postgreSQL
body: <p>I want group my data by createdAt but it is not working I don't know why...
  Only group by id which is useless for me.</p>
  
  <p>This is working:</p>
  
  <pre><code>SELECT "id", "createdAt", "updatedAt" 
  FROM "tables" AS "Table" 
  WHERE "Table"."createdAt" 
  BETWEEN '2014-04-21 20:46:25.938-04' AND '2015-04-21 20:46:25.938-04'
  GROUP BY "id";
  </code></pre>
  
  <p>This is what I want but it is not working at all ...</p>
  
  <pre><code>SELECT "createdAt", "updatedAt" 
  FROM "tables" AS "Table" 
  WHERE "Table"."createdAt" 
  BETWEEN '2014-04-21 20:46:25.938-04' AND '2015-04-21 20:46:25.938-04' 
  GROUP BY "createdAt";
  </code></pre>
  
  <p>I have error: </p>
  
  <blockquote>
    <p>ERROR:  column "Table.updatedAt" must appear in the GROUP BY clause or
    be used in an aggregate function</p>
  </blockquote>