title: How can I group by date in MySQL?
body: <p>The following MySQL query get all weeks data by user for different dates:</p>
  
  <pre><code>SELECT user_id,
         CONCAT(follow_up_date, ' - ', follow_up_date + INTERVAL 6 day) AS week,
         GROUP_CONCAT(follow_up_date)
  FROM   feedback_2
  WHERE  follow_up_date &gt; ''
  GROUP  BY WEEK(follow_up_date),
            user_id
  </code></pre>
  
  <p>Output:</p>
  
  <pre><code>---------------------------------------------------------------
  user_id |         week           | group_concat(follow_up_date)|
  ---------------------------------------------------------------
  4        2012-08-28 - 2012-09-03 | 2012-08-28,2012-08-28,2012-08-29
  14       2012-08-28 - 2012-09-03 | 2012-08-28 
  </code></pre>
  
  <p>But my requirement is, how to separate different date for same user.</p>
  
  <pre><code>---------------------------------------------------------------
  user_id |         week           | group_concat(follow_up_date)|
  ---------------------------------------------------------------
  4        2012-08-28 - 2012-09-03 | 2012-08-28,2012-08-28
  4        2012-08-28 - 2012-09-03 | 2012-08-29
  14       2012-08-28 - 2012-09-03 | 2012-08-28 
  </code></pre>