Need Help Pulling My Hair

mwichmann4

Ok I want to create a rating system like amazons. I know its not that bad with the math, but I cannot for the life of me come up with the solution. I am working with a four star system. I will be pulling the numbers from a database from 4 different fields with the book id attached. Using a switch command I will tell how many stars to show for the book based on the average. How do I do this. Thanks

Bunkermaster

😕

got a link? you lost me with the amazon thing.

BuzzLY

LOL... am I the only one that read the subject and thought mwichmann4 needed us to help him pull his hair? 😃

mwichmann4

http://www.amazon.com/exec/obidos/search-handle-form/104-2789358-3005523

Ok so you see the stars by each of the book. That is what I want to create and its all in the math. I work on it for about two hours stright last night with another college friend. We have come pretty close in figuring it out. You have any ideas please share them. And no I am not pulling my hair anymore. LOL

mwichmann4

Just goto amazon.com, search for php books and you will see the star rating system from there. As far as my own work I do not have the system to show you on my local machine.

jerdo

Buzzly, I thought the same thing. To tell the truth that's the only reason I read this thread.

BuzzLY

I am not exactly sure of the nature of your problem ... I assume that you have a number of people rating something on your site, right? Like a news article or something? I'll use an article as an example.

First, provide a way for them to rate the article, then store that value in your database in one field. You do not need four different fields. You simply need a "ratings" table, with the following fields: id (auto-increment), articleID, rating.

When displaying the article, do a search by articleID for all ratings of that article, and add all of the rating values up. For example, with a rating scale of 1 - 4, 9 people have rated the article so far. Here are the ratings:

1: 4
2: 2
3: 3
4: 2
5: 2
6: 1
7: 4
8: 3
9: 3

The total for the ratings is 4+2+3+2+2+1+4+3+3 = 24 total points. Divide 24 by 9 to get 2.67. That is your "average reader reviews."

Now, you have a choice. If you want to round to the nearest whole star, then simply use round($average). In our example, you end up with 3 stars (round(2.67) = 3).

If you want to use half stars (which I recommend), Then you have to do a little extra. Multiply the average by 2, round it, then divide by two again:

$numstars = round($average * 2) / 2;

In our example, you would end up with 2.5 stars.

I also recommend that you put the actual numerical rating next to the stars, so users can see exactly how well the article did. Star ratings are not exact:

***** SIZE=1[/SIZE]

Hope that helps, and is what you are looking for. I love doing math, so if I can help any further, let me know.

As for my comment on your "pulling your hair..." I was kidding, of course, but in all seriousness you should try to be more descriptive in your subject if you want help with something. Something like "Help with math functions" would have been a little more descriptive, and will entice more experts to read your thread.

Sxooter

What you're looking for are aggregate commands. Something like this:

select avg(score) from book_scores where book_id=123456 group by book_id;

Note that if you want to have entries for a score that don't count, you can use nulls. i.e.:

create table scores (book_id int, score int);
insert into scores values (1,2);
insert into scores values (1,3);
insert into scores values (1,4);
insert into scores values (1,3);
insert into scores values (1,NULL);
insert into scores values (1,3);

The average will be 3 (2+3+4+3+3)/5 and the null won't affect the score. That way some could review but not rate the book, and their review lacking a score wouldn't affect everybody's else's score.

mwichmann4

I got to the 3rd part of that. Where I was taking all the numbers and finding the common factore then averaging. Then dividing by two, but the last part I did not do. This really helps me alor. I will be more discriptive next time with the subject. I am really happy, thank you thank you.