How can i get all categories Id selected by Root Category

Question

I have three root category, i need all categories id for only selected root categories how can i get it. what are all the possible way to get it?

Answer 1

<?php $_helper = Mage::helper('catalog/category') ?>
<?php $categoryId = 2;?>
<?php $category = Mage::getModel('catalog/category')->load($categoryId) ?>
<?php $_categories = $category->getChildrenCategories() ?>

<?php if (count($_categories) > 0): ?>
    <ul>
        <?php foreach($_categories as $_category): ?>
            <li>
                <a href="<?php echo $_helper->getCategoryUrl($_category) ?>"><?php echo $_category->getName() ?></a>
                <?php $_category = Mage::getModel('catalog/category')->load($_category->getId()) ?>
                <?php if($_category->hasChildren()):?>
                <?php $_subcategories = $_category->getChildrenCategories() ?>
                    <ul>
                        <?php foreach($_subcategories as $_subcategory): ?>
                            <li>
                                <a href="<?php echo $_helper->getCategoryUrl($_subcategory) ?>"><?php echo $_subcategory->getName() ?></a>
                                <?php $_category2 = Mage::getModel('catalog/category')->load($_subcategory->getId()) ?>
                                <?php if($_category2->hasChildren()):?>
                                <?php $_subcategories2 = $_category2->getChildrenCategories() ?>
                                    <ul>
                                        <?php foreach($_subcategories2 as $_subcategory2): ?>
                                            <li>
                                                <a href="<?php echo $_helper->getCategoryUrl($_subcategory2) ?>"><?php echo $_subcategory2->getName() ?></a>
                                            </li>
                                        <?php endforeach; ?>
                                    </ul>
                                <?php endif; ?>

                            </li>
                        <?php endforeach; ?>
                    </ul>
                <?php endif; ?>
            </li>
        <?php endforeach; ?>
    </ul>
<?php endif; ?>

Try this

Answer 2

Please try below code. It's very simple.

     <?php

error_reporting(E_ALL);
ini_set("display_errors", 1);
$mageFilename = 'app/Mage.php';

require_once $mageFilename;

Mage::app()->setCurrentStore(Mage_Core_Model_App::ADMIN_STORE_ID);

function convert_to_csv($input_array) {
    /** open raw memory as file, no need for temp files */
    $today = date('Ymd');
    $file_path = "var/catgory_ids" . $today . ".csv";
    $temp_memory_backup = fopen($file_path, 'w');
    fwrite($temp_memory_backup, $input_array);
    fclose($temp_memory_backup);
    echo 'Data saved to csvfile.csv';
}

$catid = 2;

$sub_categories = Mage::getModel('catalog/category')->load($catid)->getChildrenCategories()->getAllIds();

$data = array();
$headers = array();

$header['cat_id'] = 1;

foreach ($sub_categories as $i => $category) {
    $data[$i]['cat_id'] = $category;
}

$tmp_columns = array();
foreach ($header as $head => $v) {
    $tmp_columns[] = $head;
}
$output.= implode(",", $tmp_columns) . "\n";

//building rows
foreach ($data as $rows) {
    $output.= implode(",", $rows) . "\n";
}

// Send the CSV file to the browser for download
convert_to_csv($output);
?>