MySQL GROUP BY query returns only one row

Question

    $q2 =   "SELECT startdate, 
             GROUP_CONCAT(summary separator '<br />') as summary, 
             GROUP_CONCAT(TIME(startdate)) AS starttime, 
             GROUP_CONCAT(TIME(enddate)) AS endtime
             FROM oc_clndr_objects
             WHERE calendarid = $calID
             GROUP BY DATE(startdate)
             ORDER BY startdate ASC";

This above query is only returning one result (3 events for one 1 date as expected) - however there is 1 event that is repeating daily, and the query does not go beyond the first startdate.

I know it has something to do with the GROUP BY clause and something about Aggregation functions but I cannot wrap my head around it. - The output is visible at http://www.deliriousdreams.co.uk/ - "DJ Schedule Test"

Any help with correcting the slightly illegal SQL query would be much appreciated.

EDIT: Alright, groovy people, amended to DATE(startdate) AS startdate. One little niggle, after that I would like to be able to sort them by DATE and then TIME (earliest first) - Obviously both DATE and TIME are derived from the startdate (DATETIME stamp) - is this possible by amending the above query or would I have to do some PHP witchcraft?

Answer 1

You are selecting startdate but grouping by DATE(startdate)

If the field startdate is datetime and you want to group by date only then you should select a data and group by a date.

Try changing your query to this

         SELECT DATE(startdate) AS startdate, 
         GROUP_CONCAT(summary separator '<br />') as summary, 
         GROUP_CONCAT(TIME(startdate)) AS starttime, 
         GROUP_CONCAT(TIME(enddate)) AS endtime
         FROM oc_clndr_objects
         WHERE calendarid = $calID
         GROUP BY DATE(startdate)
         ORDER BY startdate ASC

I hope $calID is clean variable otherwise your code is subject to SQL injections

Answer 2

And it is done! This is the solution I was looking for...

SELECT
       DATE(startdate) AS startdate, 
       GROUP_CONCAT(summary separator '<br />') as summary, 
       GROUP_CONCAT(TIME(startdate)) AS starttime, 
       GROUP_CONCAT(TIME(enddate)) AS endtime
FROM
       (SELECT * FROM oc_clndr_objects ORDER BY startdate ASC) AS temp
WHERE calendarid = $calID
GROUP BY DATE(startdate)
ORDER BY DATE(startdate) ASC