PostgreSQL：在 WITH 构造中使用列作为 ARRAY

Question

我正在尝试运行以下查询（我在评论中添加了一些我迄今为止尝试过的东西）：

WITH
res AS (
    SELECT * ...
), -- res has a column of integers called "node". I need to transform this column into an array to use it in viapath below
nodes AS (
  -- SELECT ARRAY[node] FROM res
  -- SELECT array_agg(node) FROM res
),
viapath AS (
    SELECT * FROM pgr_dijkstraVia(
        'SELECT id, source, target, cost FROM edge_net',
        nodes  -- array[54, 37, 897, 435]
    )
)
SELECT * FROM viapath;

它使用数组 [54, 37, 897, 435] 但不是“节点”。通过我的试验，我收到了 'column "nodes" does not exist'。如何将 'res' 中的 'node' 列用作 'viapath' 中的数组？

Answer 1

您可以使用子查询表达式，(select array_agg(node) from res)。

WITH
res AS (SELECT * ...),
viapath AS 
(
    SELECT * FROM pgr_dijkstraVia
    (
        'SELECT id, source, target, cost FROM edge_net',
        (select array_agg(node) from res)
    )
)
SELECT * FROM viapath;

PostgreSQL：在 WITH 构造中使用列作为 ARRAY

PostgreSQL: use column as ARRAY in a WITH construction

arrays

postgresql

common-table-expression