Question

I am trying to write a sql query but i find some difficulties.What i want is:

Lets suppose we have a table where we store the times that a video have been watched, per day.
So for example:

• day: 14/11/2011, video_id: 3539, timeswatched: 125
• and: 15/11/2011, video_id: 3539, timeswatched: 162

(so the table stores video_id,day,timeswatched)

What i want is to make a billboard/chart type which show the percentage change of the timeswatched of the 8 top viewed (for today) videos between the dates: today and yesterday.
(note that a video may have not been watched at all today or yesterday – should this be a problem or not?)

So the result should be something like this: video-id: 3539 has +23% or -44% (or..) more/less views today (we need to know how to find the 23%)

Thanks!

Answer 1

Select Top8.idvideo, (vtoday.times - vyesterday.times) / vtoday.times
From 
  (select 
     Idvideo from Nviews 
     Where day = Curdate()
   order by watches desc limit 8) top8 
  Inner join
   NViews vtoday 
       on vtoday.day = curdate()
       and vtoday.idvideo=top8.idvideo
  Left outer join
    NViews vyesterday
       On vyesterday.day= Date_add( curdate(), interval -1 day) and
           Vyesterday.idvideo = top8.idvideo