Use qty in filtered navigation [magento EE] - magento

Question

The use case I am working on is such that all products are marked is_in_stock=1 because the items can be purchased regardless of whether they are physically on hand or not. However I need to display only what has a qty value greater than zero. If the user decides they only want to see whats on hand.
I figured out how to select the correct collection by joining the cataloginventory/stock_item table with current collection and filtering for quantity. However I am little in the dark on how to apply this on the frontend and what kinds of side effects this might have since 'qty' is never passed through to solr.
$collection = Mage::getModel('catalog/product')
->getCollection()
->addAttributeToSelect('*')
->joinField('qty',
'cataloginventory/stock_item',
'qty',
'product_id=entity_id',
'{{table}}.stock_id=1',
'left')
->addAttributeToFilter('qty', array("gt" => 0));
If anyone with experience working with EE layered nav has any input on a better approach to take, advice would be appreciated, thanks.

Answer 1

Unable to post a comment at this time.
Trying to understand your problem statement. Here is what I understand from your statement.
Products can be purchased when they are In Stock and when they are Out Of Stock
Currently, you DO NOT want to display Out Of Stock products in Category and Search Pages. You want to display ONLY In Stock products.
Let me know if my understanding is correct.
If the above is the case, this can be easily achieved from the ADMIN panel.
Navigate to System > Configuration > Catalog > Inventory > Stock Options > Display out of stock products > Yes / No
Set this to Yes, to make the products visible across Category and Search (MySQL/SOLR) pages.
Set this to No, to make the products invisible across Category and Search Pages. However, in this case, Product URL will still work fine.
When using Filtered Navigation, the condition for STOCK is not checked. It checks STATUS and VISIBILITY
The above code block written is fine from performance perspective. Does this mean you are going to use QTY for filtering purpose?
If that's the case and if you are using MySQL/SOLR for Search, the product collection needs to be modified using the code block mentioned above.
This does not impact in a negative way if used as below:
After the final collection is formed using all the necessary attribute filters - default magento, then add your code block.
**Do not instantiate the collection using the code mentioned above.
$collection->joinField('qty',
'cataloginventory/stock_item',
'qty',
'product_id=entity_id',
'{{table}}.stock_id=1',
'left')
->addAttributeToFilter('qty', array("gt" => 0));
I am not really sure if I was able to answer your question. However, these are few basic points about Filtered Navigation, SOLR/MySQL Search, Category and Search Pages w.r.t In Stock/Out of Stock products.