Question

My table in Mysql is like this:

 IP       ID     area
 aaa      A        I
 aaa      A        I
 aaa      B        I  
 aaa      C        II
 bbb      A        I
 bbb      B        III
 ccc      B        I

Now I want to calculate for each area value, how many different (IP, ID) pairs are there?

How can I use both IP and ID as a whole dataset to do this?

I don’t think the following query is correct:

SELECT area, count (distinct IP, ID) from video GROUP BY area ORDER BY COUNT (distinct ip, ID)

So does anyone know how to do it?

Answer 1

SELECT area, count(*) as distinctCount FROM 
  (SELECT DISTINCT IP, ID, area FROM video) distinctVideos 
GROUP BY area
ORDER BY count(*)