MYSQL count of count? - mysql

Question

I have a mysql table like:
id, visitorid, pageid
When a visitor hits the website it stores their visitor id and the page id as a row.
I am trying to extract the number of visitors who hit the website exactly X times. (for a chart). so how many visit just one page, how many visit 2 pages...
so far I have:
SELECT COUNT(visid),visid FROM vislog GROUP BY visid ORDER BY COUNT(visid) DESC
But I don't know how to do the next part of counting the counts.
Is it possible to do as a MySQL query?

Answer 1

You can wrap your query inside another one:
SELECT
cnt AS page_visits
, COUNT(*) AS number_of_visitors
FROM
( SELECT
COUNT(*) AS cnt --- use: COUNT(DISTINCT page_id)
--- for a different count
FROM vislog
GROUP BY visid
) AS grp
GROUP BY cnt
ORDER BY number_of_visitors ;
or (I suppose this makes more sense for passing the numbers to a chart), remove the ORDER BY which is the same as putting:
ORDER BY cnt ;

Answer 2

One way to do it is to wrap this query into another one:
SELECT COUNT(visid) FROM (
SELECT COUNT(visid) AS cvisid, visid
FROM vislog
GROUP BY visid
HAVING cvisid = 2) AS c
But I think you need to get the histogram of visits: this can be done with PHP (assuming the query is the same as in the question):
$results = array();
// query preparation skipped, as it's obviously done by the OP himself
while ($row = $sth->fetch()) {
$count = $row['cvisid'];
if (isset($results[$count])) {
$results[$count]++;
}
else {
$results[$count] = 1;
}
}
Or with MySQL itself:
SELECT cvisid,
COUNT(cvisid) AS cnt
FROM (
SELECT visid,
COUNT(visid) AS cvisid
FROM vislog
GROUP BY visid ) AS c
GROUP BY cvisid

Answer 3

Raina77ow (2nd reply) returned a clean solution in his third block of code
SELECT cvisid,
COUNT(cvisid) AS cnt
FROM (
SELECT visid,
COUNT(visid) AS cvisid
FROM vislog
GROUP BY visid ) AS c
GROUP BY cvisid
thank you

Answer 4

Try using following query
SELECT COUNT(a.page_visits) AS no_of_visitors, a.page_visits AS page_count
FROM(
SELECT COUNT(DISTINCT pageid) AS page_visits
FROM vislog
GROUP BY visid) AS a
GROUP BY a.page_visits;
Hope it helps...

Answer 5

I could solve it this way:
SELECT cnt, COUNT(cnt) FROM (
SELECT COUNT(visid) as cnt FROM vislog GROUP BY visid
) x GROUP BY cnt ORDER BY cnt ASC
The little x is important.