如何在 PostgreSQL JSONB 列中查询具有异构元素的嵌套数组

Posted 2023-04-12

【中文标题】如何在 PostgreSQL JSONB 列中查询具有异构元素的嵌套数组

【英文标题】：How to query nested array with heterogeneous elements in PostgreSQL JSONB column

【发布时间】：2021-04-07 12:52:20

【问题描述】：

我在 PostgreSQL (12.5) 表 Data_Source 中有一个 JSONB 字段，里面有类似的数据：

  "C1": [
    
      "id": 13371,
      "class": "class_A1",
      "inputs": 
        "input_A1": 403096
      ,
      "outputs": 
        "output_A1": 403097
      
    ,
    
      "id": 10200,
      "class": "class_A2",
      "inputs": 
        "input_A2_1": 403096,
        "input_A2_2": 403095
      ,
      "outputs": 
        "output_A2": [
          [
            403098,
            
              "output_A2_1": 403101
            ,
            
              "output_A2_2": [
                403099,
                403100
              ]
            
          ]
        ],
        "output_A2_3": 403102,
        "output_A2_4": 403103,
        "output_A2_5": 403104
      
    
  ]

您能否建议我一些 SQL 查询来从 JSONB 字段中提取输出。 我需要得到什么结果：

输出：

name	value
output_A1	403096
output_A2	403098
output_A2_1	403101
output_A2_2	403099
output_A2_2	403100
output_A2_3	403102
output_A2_4	403103
output_A2_5	403104

有什么想法吗？

【参考方案1】：

每当遇到array，然后遇到JSONB_ARRAY_ELEMENTS()，或遇到object，则可能会应用JSONB_EACH() 函数以及辅助JSONB_TYPEOF() 函数来连续确定各自的类型。最后，结合array或object类型的结果或 not通过使用UNION ALL如 p>

WITH j AS
(
SELECT j2.*, JSONB_TYPEOF(j2.value) AS type
  FROM t,
  JSONB_EACH(jsdata) AS j0(k,v),
  JSONB_ARRAY_ELEMENTS(v) AS j1,
  JSONB_EACH((j1.value ->> 'outputs')::JSONB) AS j2
), jj AS
(
SELECT key,j1.*,JSONB_TYPEOF(j1.value::JSONB) AS type
  FROM j,
  JSONB_ARRAY_ELEMENTS(value) AS j0(v),
  JSONB_ARRAY_ELEMENTS(v) AS j1
 WHERE type = 'array'  
), jjj AS
(
 SELECT key,j0.v,JSONB_TYPEOF(j0.v::JSONB) AS type,k
   FROM jj,
   JSONB_EACH(value) AS j0(k,v)
  WHERE type IN ('array','object') 
)
SELECT key,value
  FROM
  (
   SELECT key,value,type
     FROM j  
    UNION ALL
   SELECT key,value,type
     FROM jj
    UNION ALL
   SELECT k,v,type
     FROM jjj
   ) jt  
WHERE type NOT IN ('array','object')  
UNION ALL 
SELECT k,value
  FROM jjj,JSONB_ARRAY_ELEMENTS(v) AS j0
 WHERE type IN ('array','object') 

Demo