Question

In my questions table, each post is timestamped (MM-DD-YYYY). Each individual post has a QuestionID, and a response has both a QuestionID and ResponseID. I want to run a php script that will grab all questions (all posts where ResponseID = null) and display how many questions per day.

I’d like it to be avg questions per day since June 1, 2010.

Your help is much appreciated. Thank you!

Answer 1

This gets each day, and the number of questions:

select q.myTimestamp, count(*) 
from questionsTable q 
where q.myTimeStamp >= '6/1/2010'
and q.ResponseID IS NULL
group by myTimestamp

To get the average you need both the count of days, and sum of number of questions… I would probably do this with 2 queries to MySQL and calculate in PHP.

$query1 = "select count(*) as totalCount from questionsTable where myTimestamp >= '6/1/2010' and ResponseID IS NULL";
$query2 = "select count(*) as totalDays from (select distinct myTimestamp from questionsTable where myTimestamp >= '6/1/2010' and ResponseID IS NULL) a";

$res1 = mysql_query($query1);
$res2 = mysql_query($query2);

$row1 = mysql_fetch_array($res1);
$row2 = mysql_fetch_array($res2);

$avgPostCount = ($row1['totalCount'] / $row2['totalDays']);

not optimal, but should work..

I made an assumption, that you wouldn’t want to count days where there were no questions.. otherwise it could be simplified to one query using a mysql function to get the number of days since 6/1/2010.