Magento – Are Stock and Price Alerts Ever Removed?

The problem is in Mage_Eav_Model_Entity_Attribute_Backend_Time_Created::beforeSave. This line ends up swapping the month and day:

$zendDate = Mage::app()->getLocale()->utcDate(null, $date, true, $this->_getFormat($date));

This happens to just about all entity types including products and customers, and happens during creation and normal save events, in both CE >= 1.8.x and EE >= 1.13.x.

Override this model in your own module, and replace the beforeSave method with this:

public function beforeSave($object)
{
    $attributeCode = $this->getAttribute()->getAttributeCode();
    $date = $object->getData($attributeCode);
    if (is_null($date)) {
        if ($object->isObjectNew()) {
            $object->setData($attributeCode, Varien_Date::now());
        }
    } else {
        // ADD THIS
        $date = strtotime($date);

        // convert to UTC
        $zendDate = Mage::app()->getLocale()->utcDate(null, $date, true, $this->_getFormat($date));
        $object->setData($attributeCode, $zendDate->getIso());
    }

    return $this;
}

This also needs to be corrected on the way out of the database. Replace afterLoad with this:

public function afterLoad($object)
{
    $attributeCode = $this->getAttribute()->getAttributeCode();
    $date = $object->getData($attributeCode);

    // ADD THIS
    if (!is_null($date)) {
        $date = strtotime($date);
    }

    $zendDate = Mage::app()->getLocale()->storeDate(null, $date, true, $this->_getFormat($date));
    $object->setData($attributeCode, $zendDate->getIso());

    parent::afterLoad($object);

    return $this;
}

Edit: Here is an example of how to override this class.

<global>
    <models>
        <eav>
            <rewrite>
                <entity_attribute_backend_time_created>Mycompany_Mymodule_Model_Eav_Entity_Attribute_Backend_Time_Created</entity_attribute_backend_time_created>
            </rewrite>
        </eav>
    </models>
</global>

Then create the file app\code\local\Mycompany\Mymodule\Model\Eav\Entity\Attribute\Backend\Time\Created.php

You can show the products alerts statistics in admin for all customers using collection like

protected function _prepareCollection()
{
    $productsTable = Mage::getSingleton('core/resource')->getTableName('catalog/product');
    $c = Mage::getModel('productalert/stock')->getCollection();
    $c->getSelect()
        ->columns(array('cnt' => 'count(*)', 'last_d'=>'MAX(add_date)', 'first_d'=>'MIN(add_date)'))
        ->joinInner(array('e'=> $productsTable), 'e.entity_id = product_id', array('sku'))
        ->where('send_count=0')
        ->group(array('website_id', 'product_id'))
    ;

    $this->setCollection($c);
    return parent::_prepareCollection();
} 

It's form the free alerts extension.