如何编辑此MySQL查询以包括带有count和avg的额外列？

Question

This query:

select p.visitor_id , p.url, avg(p.duration), count(*) as sum_pages
from pages p
where visitor_id = 1
group by p.visitor_id , p.url
having avg(p.duration) > (select avg(p2.duration)
                          from pages p2
                          where p2.visitor_id = p.visitor_id
                         );

produces this hypothetical table:

visitor_id ---- url ---- duration --- sum_pages
1 ------------ home ------- 5 ------- 20
1 ------------ about ------ 8 ------- 12
1 ------------ contact ---- 2 ------- 13
1 ------------ services --- 2 ------- 18

What it does: Takes the average duration number of the whole table, and checks if the average duration URL is greater. If yes, it displays the number.

I want to do the same thing and this time to add the pageviews. Each row is counted as a pageview.

How do I achieve this?

Answer 1

I found a way to achieve this but not sure about the performance of the query:

select
visitor_id, 
url,
sum(duration), 
avg(duration),
count(*) as sum_pages
from pages p 
where visitor_id='1' 
group by visitor_id,url
having sum(duration) > (select avg(duration)
                         from pages
                         where visitor_id=p.visitor_id
                       )
 and sum_pages > (select count(*)/(select count(distinct url) from pages where visitor_id=p1.visitor_id)
                   from pages p1
                  where p1.visitor_id=p.visitor_id
                  )
 ;    

DEMO