ThinkPHP菜单无极分类实现详解与优化

// 父菜单ID
$parent_id = 0;
// 查询条件
$where = [
    'parent_id' => $parent_id,
];
// 获取所有菜单
$menu = D('Menu')->where($where)->order('id asc')->select();
// 循环处理菜单
foreach ($menu as $key => $value) {
    // 获取子菜单
    $child_menu = D('Menu')->where(['parent_id' => $value['id']])->order('id asc')->select();
    // 如果有子菜单
    if (!empty($child_menu)) {
        // 处理子菜单
        foreach ($child_menu as $k => $v) {
            // 获取子菜单的子菜单
            $sub_menu = D('Menu')->where(['parent_id' => $v['id']])->order('id asc')->select();
            // 如果有子菜单
            if (!empty($sub_menu)) {
                // 处理子菜单的子菜单
                foreach ($sub_menu as $kk => $vv) {
                    // 将子菜单的子菜单添加到子菜单数组中
                    $child_menu[$k]['child_menu'][] = $vv;
                }
            }
        }
    }
    // 将子菜单添加到菜单数组中
    $menu[$key]['child_menu'] = $child_menu;
}