Configurable Products - how do I get data from the first child product?

Question

I'm trying to get a SKU from the first child item of a configurable product.

For a simple product, this works fine:

$product_id = Mage::registry('current_product')->getSku();

But on a configurable product I want it to show a SKU from a child product instead (need this for a remarketing add-in).

I'll end up with code something like the following - but this seems overly complex. Can this be simplified down a bit?

if($_product->getTypeId() == "configurable") {
    $conf = Mage::getModel('catalog/product_type_configurable')->setProduct($_product);
    $simple_collection = $conf->getUsedProductCollection()->addAttributeToSelect('*')->addFilterByRequiredOptions();
    $_hassku = false
    foreach($simple_collection as $simple_product){
        if($_hassku == "false") {
            echo $simple_product->getSku()
            $_hassku=="true" 
        }
    }

} else {
  $product_id = Mage::registry('current_product')->getSku();
};

If configurable, set a variable as 'false.' Do a 'foreach' - on the first one, it'll set the variable to true, and thus return only the one sku for the product.

Answer 1

Given $_product is your configurable product, use:

$_firstSimple = $_product->getTypeInstance()
    ->getUsedProductCollection()              // collection of associated products
    ->addAttributeToSelect('sku')             //  - with SKU attribute
    ->setPageSize(1)                          //  - limit to one row
    ->getFirstItem();                         //  - load and return first row

Answer 2

Interesting code. I think you can accomplish the same thing like this:

    echo(PHP_EOL.'<br>start test code');
            $cabac_childIds = Mage::getResourceSingleton('catalog/product_type_configurable')->getChildrenIds($_product->getId(), true);
            $cabac_getSimpleId = current($cabac_childIds[0]);
            $cabac_mungo = Mage::getResourceModel('catalog/product_collection')
                                        ->addAttributeToSelect('sku')
                                        ->addIdFilter(array($cabac_getSimpleId))
                                        ;

            $product_id = $cabac_mungo->getFirstItem()->getSku() 
            echo (PHP_EOL.'<br>'.$product_id);                    
    echo(PHP_EOL.'<br>end test code');

Note that the object returned from getChildrenIds() is an array of array of simple product ids.

Answer 3

You can simplify it a little as follow.

$simpleProduct = Mage::getModel('catalog/product_type_configurable')
    ->getUsedProductCollection($_product)
    ->addAttributeToSelect('sku')
    ->addFilterByRequiredOptions()
    ->getFirstItem();