Cara melintasi struktur struktur pohon hierarkis ke belakang menggunakan kueri rekursif

PEMBARUAN 2: Saya menulis ulang kueri rekursif asli sehingga semua akumulasi/agregasi dilakukan di luar bagian rekursif. Ini harus berkinerja lebih baik daripada versi sebelumnya dari jawaban ini. Ini sangat mirip dengan jawaban dari @a_horse_with_no_name untuk pertanyaan serupa.

  WITH 
    RECURSIVE search_graph(edge, from_node, to_node, length, area, start_node) AS
    (
        SELECT edge, from_node, to_node, length, area, from_node AS "start_node"
        FROM tree
        UNION ALL
        SELECT o.edge, o.from_node, o.to_node, o.length, o.area, p.start_node
        FROM tree o
    JOIN search_graph p ON p.from_node = o.to_node
    )
    SELECT array_agg(edge) AS "edges"
       -- ,array_agg(from_node) AS "nodes"
          ,count(edge) AS "edge_count"
          ,sum(length) AS "length_sum"
          ,sum(area) AS "area_sum"
    FROM search_graph
    GROUP BY start_node
    ORDER BY start_node
;

Hasil seperti yang diharapkan:

 start_node | edges       | edge_count | length_sum |  area_sum
------------+-------------+------------+------------+------------
  1         | {A}         |          1 |        1.1 |       0.9
  2         | {B}         |          1 |        1.2 |       1.3
  3         | {C}         |          1 |        1.8 |       2.4
  4         | {D,B,A}     |          3 |        3.5 |       3.5
  5         | {E,D,C,B,A} |          5 |        6.4 |       6.8