It works beautifully if I'm trying to get collection but it won't for single product by SKU. for example:
$product = Mage::getModel('catalog/product')->loadByAttribute('sku', $_sku);
echo $test = $product->getSelect()->__toString();
How can I get sql for a single product can I? or I must get collection with filter by sku then getSelect()....
... after a quick research ...
$products = Mage::getModel('catalog/product')
->getCollection()
->addAttributeToSelect('*')
->addAttributeToFilter('status', array('eq' => Mage_Catalog_Model_Product_Status::STATUS_ENABLED))
->addAttributeToFilter('sku',$_sku);
it does the job.