magento Get Products from Database Get product ID by SKU
Example
$sku = 'some-sku';
$productId = Mage::getModel('catalog/product')->getIdBySku($sku);
if($productId){
//sku exists
}
$sku = 'some-sku';
$productId = Mage::getModel('catalog/product')->getIdBySku($sku);
if($productId){
//sku exists
}
