[php] Magento addFieldToFilter: Two fields, match as OR, not AND

There is a bit of confusion going on here, but let me try to clarify things:

Lets say you wanted sql that looked something like:

SELECT 
    `main_table`.*, 
    `main_table`.`email` AS `invitation_email`, 
    `main_table`.`group_id` AS `invitee_group_id` 
FROM 
    `enterprise_invitation` AS `main_table` 
WHERE (
    (status = 'new') 
    OR (customer_id = '1234')
)

In order to achieve this, your collection needs to be formatted like this:

$collection = Mage::getModel('enterprise_invitation/invitation')->getCollection();

$collection->addFieldToFilter(array('status', 'customer_id'), array(
array('status','eq'=>'new'),
array('customer_id', 'eq'=>'1234') ));

Now to see what this looks like you can always echo the query that this creates by using

echo $collection->getSelect()->__toString();