AWS Athena - Querying JSON - Searching for Values - json

Question

I have nested JSON files on S3 and am trying to query them with Athena.
However, I am having problems to query the nested JSON values.
My JSON file looks like this:
{
"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"
}
What I'm trying to do is to query the "stats" field value where name=impressions.
So ideally something like:
SELECT id, account_id, stats.values.value WHERE stats.name='engagement'
AWS example: https://docs.aws.amazon.com/athena/latest/ug/searching-for-values.html
Any help would be appreciated.

Answer 1

You can query the JSON with the following table definition:
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/';
Now, the value column is available through the following unnesting:
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';