How to add product updated date as sort order using custom extension

Question

I want to add product updated date as sort order but I don't want to add Updated date field in product setting page which means if admin updates a product, it's edited date should be detected automatically.

Ref:

I want to achieve this using custom module.

I am using magento 1.9.0.1.

Answer 1

Magento provide in built field "updated_at" in table "catalog_product_entity", you can used that field. You need to overide list.php file to in custom extension to override sorting functionlity work with this field.

For List.php override, you need to do following code :

In your extension config.xml file write following :

<blocks>
      <myextension>
        <class>Mymodule_Myextension_Block</class>
      </myextension>
            <catalog>
                <rewrite>
                    <product_list_toolbar>Mymodule_Myextension_Block_Catalog_Product_List_Toolbar</product_list_toolbar>
                </rewrite>
            </catalog>
    </blocks>

And create Block file Mymodule/Myextension/Block/Catalog/Product/List/Toolbar.php code:

<?php
class Mymodule_Myextension_Block_Catalog_Product_List_Toolbar extends Mage_Catalog_Block_Product_List_Toolbar
{
}
?>

And there is function _getProductCollection() which create collection, you need to customized this collection.