Nice article!

The query can also be written as:

SELECT actor_name AS actorName, 
       Sum(CASE 
             WHEN acr.rating_name = 'excellent' THEN 1 
             ELSE 0 
           END)   AS total_excellent, 
       Sum(CASE 
             WHEN acr.rating_name = 'better' THEN 1 
             ELSE 0 
           END)   AS total_better, 
       Sum(CASE 
             WHEN acr.rating_name = 'good' THEN 1 
             ELSE 0 
           END)   AS total_good 
FROM   actor_survey acs 
       LEFT JOIN actor_rating acr 
              ON acs.rating_id = acr.id 
GROUP  BY actorname

But I understand the posted query is for the sake of the purpose of this article series. :D