这里没有用递归查询，而是用得另一种处理方法
思路：获取到数据库的所有分类，通过代码，根据pid，返回分类树，
方法代码如下：
/** * 分类树 */ public static function getTree($data){ $items = []; foreach ($data as $v){ //$v['category_id'] = $v['id'];这里需要自己做下转换，把id转换为category_id $items[$v['category_id']] = $v; //unset($v['id']); } //halt($items); $tree = []; foreach ($items as $id=>$item){ if(isset($items[$item['pid']])){ $items[$item['pid']['list']][] = &$items[$id]; }else{ $tree = &$items[$id]; } } return $tree; }数据库的数据为：
调用分类树之前：(我在查询返回后，就把id转换为category_id了，下面得category_id就是数据库对应得id)
^ array:11 [ 0 => array:3 [ "category_id" => 11 "name" => "小米8" "pid" => 2 ] 1 => array:3 [ "category_id" => 10 "name" => "显示器" "pid" => 6 ] 2 => array:3 [ "category_id" => 9 "name" => "主板" "pid" => 6 ] 3 => array:3 [ "category_id" => 8 "name" => "联想" "pid" => 5 ] 4 => array:3 [ "category_id" => 7 "name" => "戴尔" "pid" => 5 ] 5 => array:3 [ "category_id" => 6 "name" => "华硕" "pid" => 5 ] 6 => array:3 [ "category_id" => 5 "name" => "电脑" "pid" => 0 ] 7 => array:3 [ "category_id" => 4 "name" => "小米10" "pid" => 2 ] 8 => array:3 [ "category_id" => 3 "name" => "红米" "pid" => 2 ] 9 => array:3 [ "category_id" => 2 "name" => "小米" "pid" => 1 ] 10 => array:3 [ "category_id" => 1 "name" => "手机" "pid" => 0 ] ]调用分类树之后：
^ array:2 [ 0 => array:4 [ "category_id" => 5 "name" => "电脑" "pid" => 0 "list" => array:3 [ 0 => array:3 [ "category_id" => 8 "name" => "联想" "pid" => 5 ] 1 => array:3 [ "category_id" => 7 "name" => "戴尔" "pid" => 5 ] 2 => array:4 [ "category_id" => 6 "name" => "华硕" "pid" => 5 "list" => array:2 [ 0 => array:3 [ "category_id" => 10 "name" => "显示器" "pid" => 6 ] 1 => array:3 [ "category_id" => 9 "name" => "主板" "pid" => 6 ] ] ] ] ] 1 => array:4 [ "category_id" => 1 "name" => "手机" "pid" => 0 "list" => array:1 [ 0 => array:4 [ "category_id" => 2 "name" => "小米" "pid" => 1 "list" => array:3 [ 0 => array:3 [ "category_id" => 11 "name" => "小米8" "pid" => 2 ] 1 => array:3 [ "category_id" => 4 "name" => "小米10" "pid" => 2 ] 2 => array:3 [ "category_id" => 3 "name" => "红米" "pid" => 2 ] ] ] ] ] ]json格式展示效果：
这就完成了，根据pid分类的效果。
