Question

I have a MySQL query:

SELECT COUNT(*) AS total,  DATE_FORMAT(event.serverTime,'%Y-%m-%d') AS sdate
                    FROM event
                    WHERE
                    event.serverTime >= :startDate
                    AND event.serverTime <= :endDate 
                    GROUP BY sdate;

Which correctly returns something like:

2011-08-10 => 5  
2011-08-15 => 6

However, I would like to also get the dates where there was 0 counts. So assuming startDate is 2011-08-10 and endDate is 2011-08-15, I would see:

2011-08-10 => 5  
2011-08-11 => 0  
2011-08-12 => 0  
2011-08-13 => 0  
2011-08-14 => 0  
2011-08-15 => 6

I am using PHP so in theory I could do some complex looping and fill up the gaps somehow, but I am wondering if there is a better solution?

Note that if no good MySQL solution exist, I’m also open to good PHP solutions

Answer 1

You need to make a table with dates and join against that.

table temp_dates
id integer auto_increment PK
mydate date  <<-- consecutive dates

Now do the following query

SELECT count(e.servertime) as total
       , td.mydate as sdate
FROM event e
RIGHT JOIN temp_dates td ON (td.mydate = date(e.servertime))
WHERE td.mydate BETWEEN :startdate AND :enddate
GROUP BY td.mydate 
HAVING total = 0