how to get attribute values (select type) from a product collection?

Question

I need to retrieve all values of an attribute (multi-option select type) from a filtered collection of products.

First i want to get a collection of products, then filter this collection based on certain category and certain attribute.For remaining products in the collection, I want to retrieve the values (unique) of my multi-option select attribute.

So far I have some code that doesn't work

$attributeCode = 'compatible_printers';
$ctname=$_GET['ctn'];

$collection = Mage::getModel('catalog/product')->getCollection();

$collection->addAttributeToSelect('name'); 
$collection->addAttributeToSelect('manufacturer');
$collection->addAttributeToSelect('ink_type');
$collection->addAttributeToSelect($attributeCode); // this is the required attribute

$collection->addFieldToFilter(array(
array('attribute'=>'manufacturer','eq'=>$ctname), 
 )); 


$collection->addFieldToFilter(array(
array('attribute'=>'ink_type','eq'=>'Laserjet Toner'), 
 )); 
$collection->addAttributeToFilter($attributeCode, array('notnull' => true));
    $collection->addAttributeToFilter($attributeCode, array('neq' => ''));

// i m trying to get the attribute values in the following array
$usedAttributeValues = array_unique($collection->getColumnValues($attributeCode));

I have looked for similar questions and found some anwsers but they don't work for me. Can someone advice how to make the above code work?

Answer 1

You'll need to get a collection of the desired products and iterate through it to get the attribute values. Like this..

$attributeCode = 'compatible_printers';
$ctname = $_GET['ctn'];
$usedAttributeValues = array();

$collection = Mage::getModel('catalog/product')->getCollection()
    ->addAttributeToSelect(array('name', 'manufacturer', 'ink_type', $attributeCode))
    ->addAttributeToFilter('manufacturer', $ctname)
    ->addAttributeToFilter('ink_type', 'Laserjet Toner')
    ->addAttributeToFilter($attributeCode, array('notnull' => true))
    ->addAttributeToFilter($attributeCode, array('neq' => ''));

foreach ($collection as $product) {
    $usedAttributeValues[] = $product->getData($attributeCode);
}

$usedAttributeValues = array_unique($usedAttributeValues);

Answer 2

Try

$attributeCode = 'compatible_printers';

$usedAttributeValues = array();
foreach($collection as $product){
   // get unique code
   $usedAttributeValues[$product->getData($attributeCode)] = $product->getAttributeText($attributeCode) 
}

Answer 3

Please try the below snippet, i think this could work

$attributeCode = 'compatible_printers';
$ctname = $_GET['ctn'];
$usedAttributeValues = array();

$collection = Mage::getModel('catalog/product')->getCollection()
    ->addAttributeToSelect('*')  //selected all attributes, if you want you can name it
    ->addAttributeToFilter('manufacturer', $ctname)
    ->addAttributeToFilter('ink_type', 'Laserjet Toner');    

foreach ($collection as $product) {
    print $product->getId(); //prints product id
    print $product->getSku(); //prints productsku id

    //Next comes your attribute options related to this product
    echo $product->getResource()->getAttribute($attributeCode)->getFrontend()->getValue($product); //It will be comma seprated values


}