"Ambigious select statement" error resulting from join

[gebrial]

In the admin panel, when opening the page at reports->products->"low stock", we get an error page. The report says (among other things):

SQLSTATE[23000]: Integrity constraint violation: 1052 Column 'qty' in where clause is ambiguous

A quick fix for this is to go to the class Etailer_Backorders_Model_Observer_Adminhtml and comment out the lines in the function joinFieldsToCollection. I've seen other solutions to this problem where they define a 'filter_index' when joining, but I'm not sure how to implement that here.

[rjocoleman]

@gebrial I'm happy to take a PR for this, but I don't use this report myself so I won't get to it soon due to other pressing commitments.

[gebrial]

@rjocoleman no problem. I'll try to find a better solution but I thought it was important to make a note of this in case others came across the same problem.

[captainyoung]

Problem is in /app/code/core/Mage/Reports/Model/Resource/Product/Lowstock/Collection.php
Line 239
$this->getSelect()->where('qty < ?', $notifyStockExpr);

Should be:
$where = $this->_inventoryItemTableAlias . '.qty < ?';
$this->getSelect()->where($where, $notifyStockExpr);

So you have to extend Mage_Reports_Model_Resource_Product_Lowstock_Collection
and override:
public function useNotifyStockQtyFilter

I will put in a pull request.