title: Mysql left join on self or similar
body: <p>I have a query like this:</p>
  
  <pre><code>SELECT SUM(spend.price) AS total, WEEKDAY(spend.date) AS weekday
  FROM spend
  WHERE spend.date BETWEEN '2012-11-01' AND '2012-11-07'
  GROUP BY WEEKDAY(spend.date) ;
  </code></pre>
  
  <p>Right now the query gives me only the days in which the user had some payments.</p>
  
  <pre><code>total weekday
  60    2
  10    3
  3     5
  3     6
  </code></pre>
  
  <p>But instead I want to give me 0 (zeros) for every day without payments.</p>
  
  <pre><code>total weekday
  0     1
  60    2
  10    3
  0     4
  3     5
  3     6
  0     7
  </code></pre>
  
  <p>Table schema <a href="http://sqlfiddle.com/#!2/9d1ec" rel="nofollow">here</a>.</p>