MySQL Join/sum/sort

Question

Hi and thanks for taking a look at my issue.

The problem: I have 2 tables, one for ratings and one for profiles. 'ratings' contains one rating a row with a column that associates the row with an ID from 'profiles' named 'profileID'. 'ratings' has a column 'stars' that contains an int up to 5.

I want to get the top 5 profiles with the most ratings. I tried to get the SUM(ratings.stars) where rating.profileID = profiles.ID but that doesn't work out since i'm not that good at MySQL.

Thanks

Answer 1

SELECT  a.ID, SUM(b.stars) TotalRating
FROM    profiles a
        INNER JOIN ratings b    
            ON a.ID = b.ProfileID
GROUP   BY a.ID
ORDER   BY TotalRating DESC
LIMIT   5

This will basically give the top 5 profiles that has the greatest ratings. One problem with this query is that it doesn't support ties.

Answer 2

Totalling the ratings would make a product that has 100 two star ratings appear above a product that has 10 five star ratings. Probably better to use an average for rank?

SELECT profiles.ID,AVG(stars) as avg_rating
FROM profiles,ratings
WHERE profiles.ID = ratings.profileID
GROUP BY  profiles.ID
ORDER BY avg_rating DESC
LIMIT 5;

Your question states that you want to list the profiles with the most ratings. If that is the case use COUNT(stars) instead of AVG(stars):

SELECT profiles.ID,COUNT(stars) as cnt_rating
FROM profiles,ratings
WHERE profiles.ID = ratings.profileID
GROUP BY  profiles.ID
ORDER BY cnt_rating DESC
LIMIT 5;

Hope this helps!