Filter a product collection by two categories in Magento

Question

Hi

I'm trying to find products that are in two categories. I've found an example to get products that are in category1 OR category2. http://www.alphadigital.cl/blog/lang/en-us/magento-filter-by-multiple-categories.html I need products that are in category1 AND category2.

The example in the blog is:

class ModuleName_Catalog_Model_Resource_Eav_Mysql4_Product_Collection
  extends Mage_Catalog_Model_Resource_Eav_Mysql4_Product_Collection{

  public function addCategoriesFilter($categories){

  $alias = 'cat_index';
  $categoryCondition = $this->getConnection()->quoteInto(
    $alias.'.product_id=e.entity_id AND '.$alias.'.store_id=? AND ',
    $this->getStoreId()
  );

  $categoryCondition.= $alias.'.category_id IN ('.$categories.')';

  $this->getSelect()->joinInner(
    array($alias => $this->getTable('catalog/category_product_index')),
    $categoryCondition,
    array('position'=>'position')
  );

  $this->_categoryIndexJoined = true;
  $this->_joinFields['position'] = array('table'=>$alias, 'field'=>'position' );

  return $this;

  }
}

When I'm using this filter alone it perform OR query on several categories. When I combine this filter with prepareProductCollection of Mage_Catalog_Model_Layer it somehow remove the filter effect.

How can I change the filter to AND and combine it with prepareProductCollection?

Thanks

Thanks

Answer 1

I think that it will be enough to call addCategoryFilter() twice on your product collection - once for each category. I have not tested it though, so might be wrong.

Answer 2

I am also working on this to no avail, it was available in magento 1.3 using the attribute filter with finset on the category_ids column, however this was moved into the index table from the entity table and now no longer works.

There is one possible solution, but requries an override function which I found here

But this solution is far from ideal.