加入和过滤 postgres 数据库中的 json 文本字段

Question

我正在使用 postgres v.10 数据库

所以在我的示例中，我需要 return 所有空置但通电的建筑物。

我有一个 table，里面有所有的建筑，我可以在其中过滤掉空的建筑。

我的问题是有关电力的信息需要支付费用 table，而我需要的信息存储在 json 格式的文本字段中。它可能看起来像这样：

{"splitkey_hash":{"100":[{"part":"0.0","notes":"blabla","uid":"100_0","id":"100","active_from":"2020-01-01"},{"part":"1.0","notes":"roar","uid":"100_1","id":"100","active_from":"2020-06-01"},{"part":"1.0","notes":null,"uid":"100_2","id":"100","active_from":"2021-01-01"}],"200":[{"part":"0.0","notes":null,"uid":"200_0","id":"200","active_from":"2015-01-01"}],"300":[{"part":"1.0","notes":null,"uid":"300_0","id":"300","active_from":"2013-01-01"}],"400":[{"part":"1.0","notes":"abc","uid":"400_0","id":"400","active_from":"2019-01-01"},{"part":"1.0","notes":null,"uid":"400_1","id":"400","active_from":"2020-09-01"}]}}

JSON格式：

{
  "splitkey_hash": {
    "100": [
      {
        "part": "0.0",
        "notes": "blabla",
        "uid": "100_0",
        "id": "100",
        "active_from": "2020-01-01"
      },
      {
        "part": "1.0",
        "notes": "roar",
        "uid": "100_1",
        "id": "100",
        "active_from": "2020-06-01"
      },
      {
        "part": "1.0",
        "notes": null,
        "uid": "100_2",
        "id": "100",
        "active_from": "2021-01-01"
      }
    ],
    "200": [
      {
        "part": "0.0",
        "notes": null,
        "uid": "200_0",
        "id": "200",
        "active_from": "2015-01-01"
      }
    ],
    "300": [
      {
        "part": "1.0",
        "notes": null,
        "uid": "300_0",
        "id": "300",
        "active_from": "2013-01-01"
      }
    ],
    "400": [
      {
        "part": "1.0",
        "notes": "abc",
        "uid": "400_0",
        "id": "400",
        "active_from": "2019-01-01"
      },
      {
        "part": "1.0",
        "notes": null,
        "uid": "400_1",
        "id": "400",
        "active_from": "2020-09-01"
      }
    ]
  }
}

Building_id = id (json)
Elektricity active = "part": "1.0" (json)
Not active = "part": "0.0" (json)

所以如果我想问 buildung 100 是否在 2020-02-01 激活了电力，答案应该是否定的。但是2020-06-01之后就是Yes了

希望你们明白我在找什么？我想以某种方式将 json 中的信息与我所有的空建筑 ID 结合起来，并使用日期进行过滤。

Answer 1

假设建筑物 id 是整数类型，则以下查询 returns 给定 ref_date 的所有具有 active = true 或 false 的空建筑物 :

来自 PostgreSQL v12 :

SELECT DISTINCT ON ( o->'id')
       o->'id'
     , first_value(o->>'part') OVER(PARTITION BY o->'id' ORDER BY (o->>'active_from') :: date DESC) = '1.0' AS active -- = true if active, false if not active
  FROM (your_empty_building_id_list) AS l
 INNER JOIN 
     ( your_cost_table AS t
       CROSS JOIN LATERAL jsonb_path_query((t.your_json_column :: jsonb)->'splitkey_hash'
, '$.*[*]') AS o
     )
    ON l.id = (o->>'id') :: integer
WHERE (o->>'active_from') :: date <= ref_date -- ref_date to be replaced by the effective date used for the query

PostgreSQL v12 之前：

SELECT DISTINCT ON ( o->'id')
       o->'id'
     , first_value(o->>'part') OVER(PARTITION BY o->'id' ORDER BY (o->>'active_from') :: date DESC) = '1.0' AS active -- = true if active, false if not active
  FROM (your_empty_building_id_list) AS l
 INNER JOIN 
     ( your_cost_table AS t
       CROSS JOIN LATERAL jsonb_each((t.your_json_column :: jsonb)->'splitkey_hash') AS m(key, value)
       CROSS JOIN LATERAL jsonb_array_elements(m.value) AS o
     ) ON l.id = o->>'id'
    WHERE (o->>'active_from') :: date <= ref_date -- ref_date to be replaced by the effective date used for the query

查看dbfiddle

中的测试结果

加入和过滤 postgres 数据库中的 json 文本字段

joining and filtering on json textfield in postgres db

postgresql

json

join