Magento - get a parent category and all sub-sub-categories

Question

I have a single category, that has 2 subcategories. Within each of these categories, are 5 subcategories.

Is there a way to get a list of all of these 10 sub-sub-categories?

Thanks

EDIT:

Something like this:

  Main Category
       Sub_Cat_1
            Cat_1
            Cat_2
            Cat_3
       Sub_Cat_2
            Cat_4
            Cat_5
            Cat_6

  Wanting output like:

  Cat_1
  Cat_2
  Cat_3
  Cat_4
  Cat_5
  Cat_6

Thanks

Solution 1

Figured it out:

$cat = Mage::getModel('catalog/category')->load(24);
$subcats = $cat->getChildren();

foreach(explode(',',$subcats) as $subCatid)
{
  $_category = Mage::getModel('catalog/category')->load($subCatid);
  if($_category->getIsActive()) {
    $sub_cat = Mage::getModel('catalog/category')->load($_category->getId());
    $sub_subcats = $sub_cat->getChildren();
    foreach(explode(',',$sub_subcats) as $sub_subCatid)
    {
          $_sub_category = Mage::getModel('catalog/category')->load($sub_subCatid);
          if($_sub_category->getIsActive()) {
              echo '<li class="sub_cat"><a href="'.$_sub_category->getURL().'" title="View the products for the "'.$_sub_category->getName().'" category">'.$_sub_category->getName().'</a></li>';
          }
     }
  }
}

Thanks for looking!

Solution 2

All answers so far load children categories in a loop which is generally bad practice and causes execution of many SQL queries where a single one would suffice.

Performant Single Query Solution:

Let $parentCategory be your Main Category, then this collection will load all subcategories, two levels below:

$subcategoryCollection = Mage::getModel('catalog/category')
    ->getCollection()
    ->addFieldToFilter('level', $parentCategory->getLevel() + 2)
    ->addFieldToFilter('path', ['like' => $parentCategory->getData('path') . '/%']);

The path field contains the category id prefixed with all ancestor ids in the form 1/2/3. Database wise it is a column in catalog_category_entity that has an index, so comparison like this has no performance issues.

Solution 3

I have developed a recursive function to get all children of a category

$categoryObject = Mage::getModel('catalog/category')->load(CATID);
$children = MODEL_OBJECT->getChildCategories($categoryObject);

// IN MODLE FILE
public $_catIds = array();

public function getChildCategories($categoryObject){
    $categories = $categoryObject->getChildrenCategories();
    foreach ($categories as $catgory){
        if($catgory->hasChildren()){
            $this->getChildCategories($catgory);
        }
            $this->_catIds[] = $catgory->getId();
    }
    return $this->_catIds;
}

Hope this will help you.

Comments

[Andreas von Studnitz]

You should never use a "load()" inside a loop.

[Anthony]

'/%' - is correct rather than '%'. For ../8 and ../868 gets wrong result in the previous version.

[Andrew Lynch]

When looping through the results, why does getUrl() work but getName() not. What is the best way to get the name of each subcategory?

[Fabian Schmengler]

If you don't see the name, try to add addAttributeToSelect("name") after getCollection().