Question

I want to know how to use arregate sql functions for when making a Magento module. I currently have this code inside my mode;

$rake = Mage::getModel('showdown/votes')->getCollection();
$rake->addFieldToFilter('votedfor', $productid);
//$collection->groupByFilter('matchid'); //<-- what do i put here?
$sticks = count($rake);

Answer 1

I’m not sure exactly what you want to achieve as the title of you question conflicts with the code example provided.

The title asks how to count a collection, and your code example asks how to perform a group by.

So,

Collection Count

count($collection), $collection->count() or simply $collection->getSize() which will avoid the collection load (ideal if you simply require the count and nothing else)

Group By

EAV Based Collection:

    $collection->groupByAttribute('matchid');

Non EAV Based Collection:

    $collection->getSelect()->group('matchid');