Question

I need to create a mysql query for my project that’s a bit too complicated for my scope…

So, I a table of images with id and timestamp columns, along with metadata columns

I also have a table of “loves”, which has columns for id, imageid, userid, and timestamp

(userid not really important here)

Currently, I am using a LEFT JOIN to sort the images by their total number of likes

What I would like to do now is, instead, sort the images by their daily average of likes.

So, an image created today that has 5 likes associated with it should come before an image created 5 days ago with 20 likes associated.

Not even sure how to begin to approach this, any of you SQL gurus have any ideas? Cheers.

EDIT:

Using this query

SELECT images.*, 
COUNT(loves.id) AS num_loves 
FROM images 
JOIN loves ON (images.id = loves.imageid) 
GROUP BY images.id 
ORDER BY num_loves/DATEDIFF(images.timestamp,CURDATE()) 
DESC LIMIT 0 , 24

getting this error

Reference 'num_loves' not supported (reference to group function)

Still getting a handle on MySQL syntax…

Answer 1

You can use any valid expression as your ORDER BY clause. This means we just need to recall a hint of algebra:

SELECT 
  images.url,
  images.date_added
FROM IMAGES
JOIN image_likes ON image_likes.image_id = images.id
GROUP BY images.id
ORDER BY count(image_likes.id)/DATEDIFF(CURDATE(), images.date_added)