Add Coun Expression in Join to Magento Collection-Collection of common programming errors

Hi guys I’m having a hard time adding a join in Magento, well I know I can do $collection->getSelect()->join but I need to add a Count() expression in it.

What I’m concretly trying to achieve is this query:

SELECT `e`.*, COUNT(sfoi.product_id) as `count`
FROM `catalog_product_entity` 
AS `e` 
LEFT JOIN sales_flat_order_item sfoi
ON sfoi.product_id = e.entity_id 
ORDER BY `e`.`entity_id` asc, 
`e`.`entity_id` asc 

Edit:

THis is what it looks like now:

$e = Mage::getModel('catalog/product')->getCollection()->getSelect();
$e->join(array('c' => 'sales_flat_order_item'),
'e.entity_id = c.product_id',
array('count' => 'COUNT(c.product_id)'));

Outputting this gives:

SELECT `e`.*, COUNT(c.product_id) AS `count` FROM `catalog_product_entity` 
AS `e` INNER         
JOIN `sales_flat_order_item` AS `c` ON e.entity_id = c.product_id

doing this in my collection crashes the adminhtml grid. Tracing the reports it crashes here:

a:5:{i:0;s:35:"Unrecognized method 'setPageSize()'";i:1;s:4771:"#0 /app/code/core/Mage/Adminhtml/Block/Widget/Grid.php(504): Zend_Db_Select->__call('setPageSize', Array)