Question

I have a database that has two tables. These two tables are defined as:

Movie
-----
ID (int)
Title (nvchar)

MovieReview
-----------
ID (int)
MovieID  (int)
StoryRating (decimal)
HumorRating (decimal)
ActingRating (decimal)

I have a stored procedure that allows the user to query movies based on other user’s reviews. Currently, I have a temporary table that is populated with the following query:

SELECT
  m.*,
  (SELECT COUNT(ID) FROM MovieReivew r WHERE r.MovieID=m.ID) as 'TotalReviews',
  (SELECT AVG((r.StoryRating + r.HumorRating + r.ActingRating) / 3) 
      FROM MovieReview r WHERE r.MovieID=m.ID) as 'AverageRating'
FROM
  Movie m

In a later query in my procedure, I basically want to say:

SELECT
  *
FROM
  MyTempTable t
WHERE
  t.AverageRating >= @lowestRating AND 
  t.AverageRating <= @highestRating

My problem is, sometimes AverageRating is zero. Because of this, I’m not sure what to do. How do I handle this scenario in SQL?

Answer 1

I’m assuming you want to movies with zero reviews included in your result.

SELECT
  *
FROM
  MyTempTable t
WHERE
  (t.AverageRating >= @lowestRating AND 
  t.AverageRating <= @highestRating)
  OR t.TotalReviews = 0

It’s safe to test TotalReviews, because it will never be NULL.