php - 如何在 codeigniter 中获取父类别的所有子类别和孙类别？

Question

我想获取父类别的所有子类别和孙类别，直至任何级别。我的表结构是这样的。

谁能建议我如何获取所有子类别(即手机类别的三星和 S3)。

Answer 1

你需要递归。创建这样的函数(假设您使用事件记录):

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;
}

并这样调用它:

$all_categories = getCategoriesByParentId(0);

输出将是这样的:

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
        )

)

有关更多信息，这取自 OpenCart 1.5.4，catalog\model\catalog\category.php 下的 ModelCatalogCategory 类。