title: How do you combine and rename two field names on the same column and display the result?
body: <p>I'm trying to combine the fields "yellow and "blue" and rename it as "green". Then display the number of fans in each Color Category - Green Red White.</p>
  
  <p>Sample from database 'House' </p>
  
  <pre><code>|fan_id| Color|
  ---------------
     1     Yellow
     2     Red
     3     Blue 
     4     White
     5     Blue
     6     Yellow
  </code></pre>
  
  <p>Expected Result: </p>
  
  <pre><code>|fan.id| Color|
  ---------------
     4     Green
     1     Red 
     1     White
  </code></pre>
  
  <p>Here is my code on the problem; however, it seems that it is still keeping tabs on Blue and Yellow column since I see '0' popping out from the result. I'm not sure how to get the output like the expected result. </p>
  
  <pre><code>SELECT COUNT(fan.id) AS Total,
    SUM(case when Color = "Yellow" OR Color = "Blue" then 1 else 0 end) as Green,
    SUM(case when Color = "Red" then 1 else 0 end),
    SUM(case when Color = "White" then 1 else 0 end)
  FROM House
    GROUP BY Color;
  </code></pre>
  
  <p>Output: </p>
  
  <p>'''</p>
  
  <pre><code>|Total|Green|Red|White
  ------------------------
   2     |   2 |  0|   0 
   1     |   0 |  1|   0  
   2     |   2 |  0|   0 
   1     |   0 |  0|   1 
  </code></pre>