检查 BigQuery 中是否存在 JSON 键答案

【问题标题】：Check if JSON key exist in BigQuery检查 BigQuery 中是否存在 JSON 键
【发布时间】：2021-06-27 09:57:33
【问题描述】：

我正在尝试检查密钥是否存在于 JSON 中，如果存在则返回整个 JSON。

我有一个 JSON 如下：

json    
 -------- 
 "fruit":[{"apples":"5","oranges":"10"},{"apples":"5","oranges":"4"}] 
 "fruit":{"apples":"1","oranges":"15"}   
 "fruit":{"apples":"5","oranges":"1"}  
 "fruit":[{"lettuce":"7","kale": "8"}]

输出：如果 JSON ARRAY 或 JSON 对象有 key apples 则返回 key 的值

json                                                                    |Output 
 -------- -------- -------- -------- -------- -------- -------- -------- -------- -------- -------- -------- -------- --------
 "fruit":[{"apples":"5","oranges":"10"},{"apples":"5","oranges":"4"}]  |[{"apples":"5","oranges":"10"},{"apples":"5","oranges":"4"}]
 "fruit":{"apples":"1","oranges":"15"}                                 |{"apples":"1","oranges":"15"}
 "fruit":{"apples":"5","oranges":"1"}                                  |{"apples":"5","oranges":"1"}
 "fruit":[{"lettuce":"7","kale": "8"}]                                 | null

【问题讨论】：

标签： json google-cloud-platform google-bigquery

【解决方案1】：

考虑下面的例子

with `project.dataset.table` as (
  select '{"fruit":[{"apples":"5","oranges":"10"},{"apples":"5","oranges":"4"}]}' as json union all
  select '{"fruit":{"apples":"1","oranges":"15"}}' union all
  select '{"fruit":{"apples":"5","oranges":"1"}}' union all
  select '{"fruit":{"pineapples":"5","oranges":"1"}}' union all
  select '{"fruit":[{"lettuce":"7","kale": "8"}]}' 
)
select json, if(regexp_contains(json, '"apples"'), json_extract(json, '$.fruit'), null) as output 
from `project.dataset.table`

有输出

【讨论】：

嗨，米哈伊尔，我又添加了一个问题。你能帮我吗:) link
当然。回答！

【解决方案2】：

只需使用if:

with mytable as (
  select '{"fruit":[{"apples":"5","oranges":"10"},{"apples":"5","oranges":"4"}]}' as json union all
  select '{"fruit":{"apples":"1","oranges":"15"}}' union all
  select '{"fruit":{"apples":"5","oranges":"1"}}' union all
  select '{"fruit":[{"lettuce":"7","kale": "8"}]}' 
)
select if(json like '%apples%', json_extract(json, '$.fruit'), null) as output 
from mytable

【讨论】：