Re: Average Rating, like Netflix

2008-12-22 Thread Andy Shellam
Or you could wrap your entire SELECT in another query, and do an IFNULL around the rating field to convert it to 0 (or some other value important to you) as follows: SELECT movie_id, <... any other fields from movies table you want ...>, IFNULL(ratings, 0) AS rating FROM ( SELECT mo

Re: Average Rating, like Netflix

2008-12-22 Thread Brent Baisley
The ratings field would be NULL. You could also add a count in your query to tell how many ratings there were. If count is 0, you know there are no ratings. SELECT count(ratings.rating_id) AS rate_count, ... Brent Baisley On Mon, Dec 22, 2008 at 12:39 PM, Brian Dunning wrote: > If I did the left

Re: Average Rating, like Netflix

2008-12-22 Thread Brian Dunning
If I did the left join to include movies with no ratings, how would I tell if it had no ratings? If I used mysql_fetch_array in PHP, would $result['rating'] == 0, or '', or NULL, or what? On Dec 22, 2008, at 9:29 AM, Brent Baisley wrote: The biggest problem is your join condition (and no gr

Average Rating, like Netflix

2008-12-22 Thread Brian Dunning
Pretend I'm Netflix and I want to return a list of found movies, including the average of related ratings for each movie. Something like this: select movies.*, average(ratings.rating) from movies, ratings where movies.movie_id=ratings.movie_id I'm sure that's wrong in about 10 different w