title: return count 0 with mysql group by
body: <p>database table like this</p>
  
  <pre><code>============================
  = suburb_id   |   value
  = 1           |    2
  = 1           |    3
  = 2           |    4
  = 3           |    5
  </code></pre>
  
  <p>query is</p>
  
  <pre><code>SELECT COUNT(suburb_id) AS total, suburb_id 
    FROM suburbs 
   where suburb_id IN (1,2,3,4) 
  GROUP BY suburb_id
  </code></pre>
  
  <p>however, while I run this query, it doesn't give COUNT(suburb_id) = 0 when suburb_id = 0
  because in suburbs table, there is no suburb_id 4, I want this query to return 0 for suburb_id = 4, like</p>
  
  <pre><code>============================
  = total       |   suburb_id
  = 2           |    1
  = 1           |    2
  = 1           |    3
  = 0           |    4
  </code></pre>