MYSQL Query - Ordering a selection by difference of two tables (up/down votes)

[defroster]

Hello. I would really appreciate some help. Thanks!

 

Background:

This is a table containing photos. Now I would like to do a query where I order the result by 'upvotes(up)' minus(-) 'downvotes(down)' .

 

Table 'photos'
id
cat_id
type_id
title
status
dateposted	
up (int)
down(int)

At the moment I am just able to sort it by the popularity of the 'upvotes' .. see below:

$sql = "Select photos.*, categories.cat FROM videos, categories
WHERE photos.cat_id = categories.id AND photos.status ='1' ORDER BY photos.up DESC
LIMIT $start, $limit";
$result = mysql_query($sql);

 

If a photo has more up-votes than down-votes it will be a positive number.

If a photo has more down-votes than up-votes it will be a negative number.

 

And I would like to sort the query running from the highest positive number to the largest negative number.

 

I am very puzzled on how to solve this and would very much appreciate some help. Cheers /df

 

[defroster]

Problem solved. I for some reason thought it would be a lot more complicated.

ORDER BY (photos.up - photos.down) DESC