title: SQL Show Null Value Group By
body: <p>This is table in my database</p>
  
  <pre><code>+--+-------+---------+----------+--------+
  |ID|OrderID|ProductID|OrderDate |Quantity|
  | 1|1      |1        |2017-01-01|1       |
  | 2|1      |1        |2017-01-01|6       |
  | 3|1      |1        |2017-01-03|9       |
  | 4|1      |1        |2017-01-04|3       |
  | 5|1      |1        |2017-01-05|5       |
  | 6|1      |1        |2017-01-07|1       |
  | 7|1      |1        |2017-01-09|2       | 
  +--+-------+---------+----------+--------+
  </code></pre>
  
  <p>I want to show the data like this</p>
  
  <pre><code>+----------+----+
  |2017-01-01|7   |
  |2017-01-02|0   |
  |2017-01-03|9   |
  |2017-01-04|3   |
  |2017-01-05|5   |
  |2017-01-06|0   |
  |2017-01-07|1   |
  |2017-01-08|0   | 
  |2017-01-09|2   |
  +----------+----+
  </code></pre>
  
  <p>What query I should use to make it possible, I've tried to using group by OrderDate but when there is null it doesnt show</p>