title: Query with double group by?
body: <p>I'm trying to edit this query:</p>
  
  <pre><code>SELECT (WEEKDAY( date ) +1) dayofweek, COUNT( * ) count 
  FROM abanners 
  WHERE iid = ? AND banner LIKE ? 
  GROUP BY (WEEKDAY( date ) +1) 
  ORDER BY count DESC
  </code></pre>
  
  <p>With this query I get the number of entries splited by day of week, but what if I need to get the same thing splitted also by <code>banner</code>?</p>
  
  <p>So I want to have:</p>
  
  <pre><code> banner1: entries splitted by day of week
   banner2: entries splitted by day of week
  
   ex: {"banner1" : "1,3,4,1,3,5,1", "banner2": "1,3,4,1,3,5,1"}
  </code></pre>
  
  <p>How can I do?</p>