如何提取在 BigQuery 中存储为字符串的 JSON 数组

Posted 2023-03-24

【中文标题】如何提取在 BigQuery 中存储为字符串的 JSON 数组

【英文标题】：How to extract JSON array stored as string in BigQuery

【发布时间】：2020-10-02 06:46:11

【问题描述】：

我有一个与此类似的 JSON 数组

["key":"Email","slug":"customer-email","value":"[e-mail]","key":"Phone Number","slug":"mobile-phone-number","value":"123456789","key":"First Name","slug":"first-name","value":"abc","key":"Last Name","slug":"last-name","value":"xyz","key":"Date of birth","slug":"date-of-birth","value":"01/01/1990"]

但棘手的部分是，这个数组存储为字符串。所以我认为第一步是将字符串转换为数组，然后将其取消嵌套，然后按照here中的方法进行操作@

我想知道这种方法是否可行，如果可行，我猜我面临的挑战是将字符串转换为数组。如果没有，或者您有更有效的方法，请提供帮助。谢谢

【参考方案1】：

你试过json_extract_array

select json_extract_array(
  """["key":"Email","slug":"customer-email","value":"[e-mail]","key":"Phone Number","slug":"mobile-phone-number","value":"123456789","key":"First Name","slug":"first-  name","value":"abc","key":"Last Name","slug":"last-name","value":"xyz","key":"Date of birth","slug":"date-of-birth","value":"01/01/1990"]""");

【讨论】：

太神了，救了我的命

【参考方案2】：

以下是 BigQuery 标准 SQL

#standardSQL
SELECT 
  id, 
  JSON_EXTRACT_ARRAY(json_string) AS json_array
FROM `project.dataset.table`   

如果适用于您的问题中的示例数据，如下所示

#standardSQL
WITH `project.dataset.table` AS (
  SELECT 1 id, '["key":"Email","slug":"customer-email","value":"[e-mail]","key":"Phone Number","slug":"mobile-phone-number","value":"123456789","key":"First Name","slug":"first-name","value":"abc","key":"Last Name","slug":"last-name","value":"xyz","key":"Date of birth","slug":"date-of-birth","value":"01/01/1990"]' json_string
)
SELECT 
  id, 
  JSON_EXTRACT_ARRAY(json_string) AS json_array
FROM `project.dataset.table`   

输出是

Row id  json_array 
1   1   "key":"Email","slug":"customer-email","value":"[e-mail]"  
        "key":"Phone Number","slug":"mobile-phone-number","value":"123456789"  
        "key":"First Name","slug":"first-name","value":"abc"   
        "key":"Last Name","slug":"last-name","value":"xyz"     
        "key":"Date of birth","slug":"date-of-birth","value":"01/01/1990"  

从这一点开始 - 您可以使用您在问题中引用的 How do I parse value from JSON array into columns in BigQuery 中的解决方案

【讨论】：

我将相同的 JSON 数组作为 STRING 存储在我的一列中。我需要提取“值”的值，即仅 email_id 作为查询整个列的结果。我如何在单选查询中做到这一点？即字符串是 '["key":"Email","slug":"customer-email","value":"[e-mail]"' 我如何提取 '[e-mail]' 作为查询结果。