如何在codeigniter中获取父类别的所有子孙类别？

Question

我想让父类别的所有子孙类别达到任何级别。我的表结构是这样的。

任何人都可以建议我如何获得所有儿童类别（即手机类别的三星和S3）。

Answer 1

你需要递归。创建这样的函数（假设您使用活动记录）：

function getCategoriesByParentId($category_id) {
    $category_data = array();

    $category_query = $this->db->query("SELECT * FROM categories WHERE parent_category = '" . (int)$category_id . "'");

    foreach ($category_query->result() as $category) {
        $category_data[] = array(
            'category_id' => $category->category_id,
            'category_name' => $category->category_name,
            'category_alias' => $category->category_alias,
            'parent_category' => $category->parent_category
        );

        $children = getCategoriesByParentId($category->category_id);

        if ($children) {
            $category_data = array_merge($children, $category_data);
        }           
    }

    return $category_data;
}

并将其称为：

$all_categories = getCategoriesByParentId(0);

输出将如下：

Array
(
    [0] => Array
        (
            [category_id] => 14
            [category_name] => s3
            [category_alias] => s3
            [parent_category] => 13
        )

    [1] => Array
        (
            [category_id] => 13
            [category_name] => Samsung
            [category_alias] => samsung
            [parent_category] => 12
        )

    [2] => Array
        (
            [category_id] => 12
            [category_name] => Phone
            [category_alias] => phone
            [parent_category] => 0
        )

)

有关详情，请参阅OpenCart 1.5.4下ModelCatalogCategory，catalog\model\catalog\category.php下的{{1}}。

Answer 2

假设你在数组中有这些，你需要使用递归循环。

// Information from database loaded into array
$array = array(
    0    => array(
        'category_id'        => 12,
        'category_name'      => 'Phone',
        'category_alias'     => 'phone',
        'parent_category'    => 0
    ),
    // ... other rows
); 
$children = array(); // Will contain all our children and grandchildren

function FindChildrenAndGrandchildren(array $array, $parentId, $level = 0) {
    $children = array();
    foreach($array as $category) {
        if($category['parent_category'] == $parentId) {
            if($level == 0) {
                $temp = FindChildrenAndGrandchildren($array, $category['category_id'], 1);
                $category['children'] = $temp;
            }
            $children[] = $category;
        }
    }
    return $children;
}

$children = FindChildrenAndGrandchildren($array, 12); // Start search