Store multiple elements in json files in AWS Athena - sql

Question

I have some json files stored in a S3 bucket , where each file has multiple elements of same structure. For example,
[{"eventId":"1","eventName":"INSERT","eventVersion":"1.0","eventSource":"aws:dynamodb","awsRegion":"us-west-2","image":{"Message":"New item!","Id":101}},{"eventId":"2","eventName":"MODIFY","eventVersion":"1.0","eventSource":"aws:dynamodb","awsRegion":"us-west-2","image":{"Message":"This item has changed","Id":101}},{"eventId":"3","eventName":"REMOVE","eventVersion":"1.0","eventSource":"aws:dynamodb","awsRegion":"us-west-2","image":{"Message":"This item has changed","Id":101}}]
I want to create a table in Athena corresponding to above data.
The query I wrote for creating the table:
CREATE EXTERNAL TABLE IF NOT EXISTS sampledb.elb_logs2 (
`eventId` string,
`eventName` string,
`eventVersion` string,
`eventSource` string,
`awsRegion` string,
`image` map<string,string>
)
ROW FORMAT SERDE 'org.openx.data.jsonserde.JsonSerDe'
WITH SERDEPROPERTIES (
'serialization.format' = '1',
'field.delim' = ' '
) LOCATION 's3://<bucketname>/';
But if I do a SELECT query as follows,
SELECT * FROM sampledb.elb_logs4;
I get the following result:
1 {"eventid":"1","eventversion":"1.0","image":{"id":"101","message":"New item!"},"eventsource":"aws:dynamodb","eventname":"INSERT","awsregion":"us-west-2"} {"eventid":"2","eventversion":"1.0","image":{"id":"101","message":"This item has changed"},"eventsource":"aws:dynamodb","eventname":"MODIFY","awsregion":"us-west-2"} {"eventid":"3","eventversion":"1.0","image":{"id":"101","message":"This item has changed"},"eventsource":"aws:dynamodb","eventname":"REMOVE","awsregion":"us-west-2"}
The entire content of the json file is picked as one entry here.
How can I read each element of json file as one entry?
Edit: How can I read each subcolumn of image, i.e., each element of the map?
Thanks.

Answer 1

Question1: Store multiple elements in json files for AWS Athena
I need to rewrite my json file as
{"eventId":"1","eventName":"INSERT","eventVersion":"1.0","eventSource":"aws:dynamodb","awsRegion":"us-west-2","image":{"Message":"New item!","Id":101}}, {"eventId":"2","eventName":"MODIFY","eventVersion":"1.0","eventSource":"aws:dynamodb","awsRegion":"us-west-2","image":{"Message":"This item has changed","Id":101}}, {"eventId":"3","eventName":"REMOVE","eventVersion":"1.0","eventSource":"aws:dynamodb","awsRegion":"us-west-2","image":{"Message":"This item has changed","Id":101}}
That means
Remove the square brackets [ ] Keep each element in one line
{.....................}
{.....................}
{.....................}
Question2. Access nonlinear json attributes
CREATE EXTERNAL TABLE IF NOT EXISTS <tablename> (
`eventId` string,
`eventName` string,
`eventVersion` string,
`eventSource` string,
`awsRegion` string,
`image` struct <`Id` : string,
`Message` : string>
)
ROW FORMAT SERDE 'org.openx.data.jsonserde.JsonSerDe'
WITH SERDEPROPERTIES (
'serialization.format' = '1',
"dots.in.keys" = "true"
) LOCATION 's3://exampletablewithstream-us-west-2/';
Query:
select image.Id, image.message from <tablename>;
Ref:
http://engineering.skybettingandgaming.com/2015/01/20/parsing-json-in-hive/
https://github.com/rcongiu/Hive-JSON-Serde#mapping-hive-keywords