EXPLODE_JSON_OBJECT

Description

explode_json_object expands a JSON object into multiple rows, with each row containing a key-value pair. It is typically used to process JSON data and expand the JSON object into a more queryable format. This function only supports non-empty JSON objects.

explode_json_object_outer is similar to explode_json_object, but with different behavior when handling empty and NULL values. It can retain empty or NULL JSON objects and return corresponding records.

Syntax

EXPLODE_JSON_OBJECT(<json>)
EXPLODE_JSON_OBJECT_OUTER(<json>)

Parameters

Parameter	Description
<json>	json type

Return Value

When the JSON object is neither empty nor NULL, the return values of explode_json_object and explode_json_object_outer are the same. Each key-value pair generates one row, with the key as one column and the value as another column.

When the JSON object is empty or NULL:

explode_json_object will not return any rows. explode_json_object_outer will return one row, with the expanded columns being NULL.

Examples

CREATE TABLE example (
    id INT,
    value_json json
) DUPLICATE KEY(id)
DISTRIBUTED BY HASH(`id`) BUCKETS AUTO
PROPERTIES (
"replication_allocation" = "tag.location.default: 1");

INSERT INTO example VALUES
(1, '{"key1": "value1", "key2": "value2"}'),
(2, '{}'),
(3, NULL);

select * from example;

+------+-----------------------------------+
| id   | value_json                        |
+------+-----------------------------------+
|    2 | {}                                |
|    1 | {"key1":"value1","key2":"value2"} |
|    3 | NULL                              |
+------+-----------------------------------+

SELECT id, k, v
FROM example
LATERAL VIEW explode_json_object(value_json) exploded_table AS k , v;

+------+------+----------+
| id   | k    | v        |
+------+------+----------+
|    1 | key1 | "value1" |
|    1 | key2 | "value2" |
+------+------+----------+

SELECT id, k, v
FROM example
LATERAL VIEW explode_json_object_outer(value_json) exploded_table AS k, v;

+------+------+----------+
| id   | k    | v        |
+------+------+----------+
|    3 | NULL | NULL     |
|    1 | key1 | "value1" |
|    1 | key2 | "value2" |
|    2 | NULL | NULL     |
+------+------+----------+