Question

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任和间接前驱及其关系以及树层次结构中存在的所有子活动。所有子事件与前辈一起以分层方式进行。

我的表格结构如下：

前身

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，但我会很感激快速回答或制定查询的准则。

表格中的样本数据如下

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|

前身数据

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

Answer 1

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。

功能 get_activity_anc （传递act_id，然后检索所有前任或祖先活动）

CREATE OR REPLACE FUNCTION public.get_activity_anc(IN act_id integer)
  RETURNS TABLE(activity_id integer, parent_id integer) AS
$BODY$
BEGIN
    RETURN QUERY
    WITH RECURSIVE results(activity_id, parent_id) AS
    (
        SELECT  act.activity_id,
            act.parent_id
        FROM    activities act
        WHERE act.activity_id = act_id
        UNION ALL
        SELECT  t.activity_id,
            t.parent_id
        FROM    activities t
            INNER JOIN results r ON r.parent_id = t.activity_id
    )
    -- output the results
    SELECT  res.activity_id, res.parent_id
    FROM    results res
    ORDER BY activity_id;

END;
$BODY$
  LANGUAGE plpgsql VOLATILE

函数 get_activity_desc （传递act_id，然后检索所有后代或后续活动）

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

函数 get_activity_ancdesc 以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

用于返回父活动和依赖活动的分层查询

1 个答案: