Group and count orders by custom delivery date attribute

Question

I have a custom attribute delivery_date set for my orders however I want to create a collection that groups all these dates together and tells me the order count for each date. I have attempted with something like below and other methods however not having much like in returning anything:

$orders = $this->_orderCollectionFactory->create()->addAttributeToSelect('*')->addFieldToFilter('delivery_date', array('gteq' => $fromDay))->getSelect()->columns(['count' => new \Zend_Db_Expr('COUNT(delivery_date)')])->group('delivery_date');

How can this be achieved?

Answer 1

This did the trick for me:

    $orders = $this->_orderCollectionFactory->create()->addAttributeToSelect('delivery_date')->addFieldToFilter('delivery_date', array('gteq' => $fromDay));
    $orders->getSelect()->columns(['day_count' => new \Zend_Db_Expr('COUNT(*)')])->group('delivery_date');