Sql 用于返回父活动和从属活动的分层查询

我必须创建一个以activity_id为参数的函数

函数应返回活动直接前置和间接前置及其与树层次结构中存在的所有子活动的关系。 所有子活动都以分层方式与前辈一起进行

我的表格结构如下：

前任

CREATE TABLE public.predecessor
(
predecessor_id integer NOT NULL ,
current_activity_id integer,
dependent_activity_id integer,
createdby integer,
created_at timestamp without time zone NOT NULL DEFAULT now()
)

活动

CREATE TABLE public.activities
(
activity_id integer NOT NULL,
parent_id integer,
name text,
type_id integer NOT NULL DEFAULT 11
)

我知道这是一个非常简短的陈述，但我会很感激快速的回答或制定一个问题的指导方针

表中的示例数据如下所示

活动数据

activity_id|parent_id
   8000|    |            
   8100|8000|            
   8200|8000|            
   8120|8100|            
   8130|8100|            
   8140|8100|            
   8220|8200|            
   8230|8200|            
   8240|8200|            
   8241|8240|            
   8242|8240|            
   8243|8240|            
   7000|    |            
   7100|7000|            
   7200|7000|            
   7300|7000|            
   7210|7200|            
   7220|7200|            
   6100|6000|            
   6200|6000|            
   6210|6200|            
   6220|6200|            
   6230|6200|            
   6240|6200|            
   6241|6240|            
   6242|6240|            
   6243|6240|            
   6244|6240|       

前置数据

activity_id|parent_id
8100|8120
8100|8130
8100|8140
8200|8220
8200|8230
8200|8240
7000|7100
7000|7200
7000|7300
6200|6210
6200|6220
6200|6230
6200|6240
6240|6241
6240|6242
6240|6243
6240|6244

---

创建了两个函数，一个用于获取活动的祖先或前辈，另一个用于获取活动的后代或后继者

函数获取活动\u anc（传递act\u id，然后检索所有前置或祖先活动）

函数获取活动描述（传递动作id，然后检索所有子体或后续活动）

函数获取活动\u ancdesc获取活动的祖先和后代

CREATE OR REPLACE FUNCTION public.get_activity_ancdesc(IN act_id integer)
  RETURNS TABLE(activity_id integer, parent_id integer) AS
$BODY$
BEGIN
    RETURN QUERY
    WITH ANCESTOR_DESC AS 
    (
        select ga.activity_id, ga.parent_id from get_activity_anc(act_id) ga
        union
        select gad.activity_id, gad.parent_id from get_activity_desc(act_id) gad
    )
    select * from ANCESTOR_DESC AD
    ORDER BY AD.activity_id;
END;
$BODY$
  LANGUAGE plpgsql VOLATILE

CREATE OR REPLACE FUNCTION public.get_activity_desc(IN act_id integer)
  RETURNS TABLE(activity_id integer, parent_id integer, level integer, path_info integer[]) AS
$BODY$
BEGIN
     RETURN QUERY
     WITH RECURSIVE rel_tree(activity_id, parent_id, level, path_info) AS (
               SELECT activities.activity_id,
                   activities.parent_id,
                   0 AS level,
                   sortorder || array[activities.activity_id]   as path_info
                  FROM activities
                 WHERE activities.parent_id =act_id
          UNION ALL
               SELECT c.activity_id,
                   c.parent_id,
                   p.level + 1,
                   p.path_info || c.sortorder ||c.activity_id
                  FROM activities c
                JOIN rel_tree p ON c.parent_id = p.activity_id
          )
          select * from rel_tree s order by path_info;
END;
$BODY$
  LANGUAGE plpgsql VOLATILE

CREATE OR REPLACE FUNCTION public.get_activity_ancdesc(IN act_id integer)
  RETURNS TABLE(activity_id integer, parent_id integer) AS
$BODY$
BEGIN
    RETURN QUERY
    WITH ANCESTOR_DESC AS 
    (
        select ga.activity_id, ga.parent_id from get_activity_anc(act_id) ga
        union
        select gad.activity_id, gad.parent_id from get_activity_desc(act_id) gad
    )
    select * from ANCESTOR_DESC AD
    ORDER BY AD.activity_id;
END;
$BODY$
  LANGUAGE plpgsql VOLATILE