title: Group by week and select records from current week
body: <p>I have been trying to display a table of results for weekly sales using MySQL, where the results of the week should be like: </p>
  
  <pre><code>Sun - Mon - Tues - Wed - Thur - Fri - Sat
  </code></pre>
  
  <p>So I went ahead and used this query:</p>
  
  <pre><code>SELECT DATE_FORMAT(cart_calendar.datefield, '%d-%b') AS DATE
          , IFNULL(SUM(cart_daily_sales.quantity),0) AS total_sales 
  FROM cart_daily_sales 
  RIGHT JOIN cart_calendar 
           ON (DATE(cart_daily_sales.order_date) = cart_calendar.datefield)
  WHERE (cart_calendar.datefield) 
  GROUP BY WEEK(cart_calendar.datefield)
  </code></pre>
  
  <p>I know I'm almost there as this outputs all of the 52 weeks in the year, I only want the current week result unlike the above code that results to this...</p>
  
  <pre><code>'02-Jan', '09-Jan', '16-Jan', '23-Jan', '30-Jan', '06-Feb', '13-Feb', '20-Feb', '27-Feb', '06-Mar' e.t.c....
  </code></pre>
  
  <p>I know I can use the BETWEEN operator for today's date and then -7 days but this doesn't  show the current week, if today's day is Wednesday it will show the last seven days to last weeks Wednesday, not the correct week structure.</p>
  
  <p>How do I display last week's sales grouped per week?</p>