phpcms父栏目调用子栏目的办法

CREATE TABLE categories (
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(255),
    parent_id INT,
    FOREIGN KEY (parent_id) REFERENCES categories(id)
);

CREATE TABLE articles (
    id INT PRIMARY KEY AUTO_INCREMENT,
    title VARCHAR(255),
    content TEXT,
    category_id INT,
    FOREIGN KEY (category_id) REFERENCES categories(id)
);

// 控制器
namespace app\controller;

use think\Controller;
use think\Db;

class CategoryController extends Controller
{
    public function index($parent_id = 0)
    {
        // 查询父栏目下的所有子栏目
        $subCategories = Db::name('categories')
            ->where('parent_id', $parent_id)
            ->select();

        // 将子栏目传递给视图
        $this->assign('subCategories', $subCategories);

        return $this->fetch();
    }
}

<!-- category/index.html -->
<ul>
    {volist name="subCategories" id="category"}
        <li>
            {$category.name}
            <!-- 递归调用子栏目 -->
            {if condition="$category.children|default='' neq ''"}
                {include file="category/index" parent_id="$category.id"}
            {/if}
        </li>
    {/volist}
</ul>