AWS Athena - 查询 JSON - 搜索值

Question

我在 S3 上嵌套了 JSON 文件，并尝试使用 Athena 查询它们。

但是，我在查询嵌套 JSON 值时遇到问题。

我的 JSON 文件如下所示：

 {
  "id": "17842007980192959",
  "acount_id": "17841401243773780",
  "stats": [
    {
      "name": "engagement",
      "period": "lifetime",
      "values": [
        {
          "value": 374
        }
      ],
      "title": "Engagement",
      "description": "Total number of likes and comments on the media object",
      "id": "17842007980192959/insights/engagement/lifetime"
    },
    {
      "name": "impressions",
      "period": "lifetime",
      "values": [
        {
          "value": 11125
        }
      ],
      "title": "Impressions",
      "description": "Total number of times the media object has been seen",
      "id": "17842007980192959/insights/impressions/lifetime"
    },
    {
      "name": "reach",
      "period": "lifetime",
      "values": [
        {
          "value": 8223
        }
      ],
      "title": "Reach",
      "description": "Total number of unique accounts that have seen the media object",
      "id": "17842007980192959/insights/reach/lifetime"
    },
    {
      "name": "saved",
      "period": "lifetime",
      "values": [
        {
          "value": 0
        }
      ],
      "title": "Saved",
      "description": "Total number of unique accounts that have saved the media object",
      "id": "17842007980192959/insights/saved/lifetime"
    }
  ],
  "import_date": "2017-12-04"
}

我想做的是查询“stats”字段值，其中 name=impressions。

所以理想情况下是这样的：

SELECT id, account_id, stats.values.value WHERE stats.name='engagement'

AWS示例：https://docs.aws.amazon.com/athena/latest/ug/searching-for-values.html

任何帮助，将不胜感激。

Answer 1

您可以使用以下表定义查询 JSON：

CREATE EXTERNAL TABLE test(
id string,
acount_id string,
stats array<
  struct<
     name:string,
     period:string,
     values:array<
         struct<value:string>>,
     title:string
  >
 >
)
ROW FORMAT SERDE 'org.openx.data.jsonserde.JsonSerDe'
LOCATION 's3://bucket/';

现在，value可以通过以下取消嵌套来使用该列：

select id, acount_id, stat.name,x.value
from test
cross join UNNEST(test.stats) as st(stat)
cross join UNNEST(stat."values") as valx(x)
WHERE stat.name='engagement';