Magento 2 use group by in collection

Question

I've got a collection from the factory method getCollection(). The problem is that when I use get_class_methods($class) to list all the methods that the collection possesses I can't seem to find one which groups the records in the collection.
I found this How to use group by in magento collection with join query
But I don't have the group() method in my collection class. How can I group by in that case ?

Answer 1

You cannot use group directly from the collection.
But each collection has an instance of Zend_Db_Select associated to it. This is the actual query that is going to be executed when the collection is loaded.
So you can use:

$collection = ....
$collection->getSelect()->group('group_field_here');