使用mysql帮助处理线程类别层次结构

Question

GID    name                     parent_GID     status
1      HQ                                      0 # 0 means its a category
2      Blog                     1              x # x some administration stuff
3      Feedback & Support       1              x
5      Service                                 0
6      Web                      5              x
7      Advertising              6              x
8      Others                   5              x

类似于（3级）

HQ
    Blog
    Feedback & Support
Service
    Web
        Advertising
    Others

到目前为止我做了什么

SELECT * FROM groups WHERE status = 0 # get categories

打印

HQ
Services

所以我们可以做类似

的事情

# fetch categories
# get the GIDs
# fetch with foreach GID
  HQ # with GID 1 so search if there is child 1
      # SELECT * FROM groups WHERE parent_GID = 1
      Blog
      Feedback & Support
  Service # with GID 5 so search if there is child 5
      # SELECT * FROM groups WHERE parent_GID = 5
      Web
      Others

上面的问题是它的olny 2级层次结构。

任何建议进行3级全部获取？

谢谢！

Answer 1

我之前的回答可能是一个很好的起点：

Generating Depth based tree from Hierarchical Data in MySQL (no CTEs)

提示：

更改以下声明

insert into hier select parent_cat_id, cat_id, v_depth from categories where cat_id = p_cat_id;

到

insert into hier select parent_cat_id, cat_id, v_depth from categories where parent_cat_id is null;

并忘记传递一个起始的parent_cat_id！

希望这会有所帮助：）