Retrieval using JSON
Using the SELECT command to return JSON data.
In Cassandra 2.2 and later, you can use CQL SELECT keywords to retrieve data from a table in the JSON format. For more information, see What's New in Cassandra 2.2: JSON Support.
Retrieving all results in the JSON format
To get this result, insert the JSON keyword between the
SELECT command and the data specifications. For example,
:
cqlsh:cycling> select json name, checkin_id, timestamp from checkin;
[json]
------------------------------------------------------------------------------------------------------------------
{"name": "BRAND", "checkin_id": "50554d6e-29bb-11e5-b345-feff8194dc9f", "timestamp": "2016-08-28 21:45:10.406Z"}
{"name": "VOSS", "checkin_id": "50554d6e-29bb-11e5-b345-feff819cdc9f", "timestamp": "2016-08-28 21:44:04.113Z"}
(2 rows)
Retrieving selected columns in JSON format
To specify the JSON format for a selected column, enclose its name in
toJson()
. For
example:cqlsh:cycling> select name, checkin_id, toJson(timestamp) from checkin;
name | checkin_id | system.tojson(timestamp)
-------+--------------------------------------+----------------------------
BRAND | 50554d6e-29bb-11e5-b345-feff8194dc9f | "2016-08-28 21:45:10.406Z"
VOSS | 50554d6e-29bb-11e5-b345-feff819cdc9f | "2016-08-28 21:44:04.113Z"
Note: Cassandra2.2 and later return a JSON-formatted
timestamp
with
complete time zone information.