ProductListing based on Attribute in Magento - php

Question

I would like to show "Suggestions" in my product listing in Magento. I made an attribute "Suggestion" which is Yes/No and global active. Now in the listing I would like to show the suggestions first, then some text and stuff, and then the rest of products.
I tried it like this:
$_productCollection=$this->getLoadedProductCollection()
/* .... */
$_productCollection->clear()->addAttributeToFilter('suggestion', 1)->load();
But this ends in an exception:
You cannot define a correlation name '_price_rule' more than once
Now the question is, how to solve this?

Answer 1

Ok, the solution for me was a custom module, which extends the List Functionality. I added the following file:
/app/code/local/Mage/Catalog/Block/Product/List.php
With the following extending code:
protected function _getProductCollectionSuggestion()
{
$layer = Mage::getSingleton('catalog/layer');
/* #var $layer Mage_Catalog_Model_Layer */
if ($this->getShowRootCategory()) {
$this->setCategoryId(Mage::app()->getStore()->getRootCategoryId());
}
// if this is a product view page
if (Mage::registry('product')) {
// get collection of categories this product is associated with
$categories = Mage::registry('product')->getCategoryCollection()
->setPage(1, 1)
->load();
// if the product is associated with any category
if ($categories->count()) {
// show products from this category
$this->setCategoryId(current($categories->getIterator()));
}
}
$origCategory = null;
if ($this->getCategoryId()) {
$category = Mage::getModel('catalog/category')->load($this->getCategoryId());
if ($category->getId()) {
$origCategory = $layer->getCurrentCategory();
$layer->setCurrentCategory($category);
}
}
$this->_productCollection = $layer->getProductCollection();
$this->_productCollection->addAttributeToFilter('suggestion', 1);
if($this->_productCollection->count()) {
foreach($this->_productCollection as $_productKey => $_product) {
if($_product->getSuggestion() == 0 || !$_product->getSuggestion()) {
}
}
}
$this->prepareSortableFieldsByCategory($layer->getCurrentCategory());
if ($origCategory) {
$layer->setCurrentCategory($origCategory);
}
return $this->_productCollection;
}
Then I loaded this method in the List.phtml and it worked :)
Thanks for reading anyway! Maybe this code helps someone!