STRIP_NULL_VALUE

Description

The STRIP_NULL_VALUE function converts NULL values in JSON to NULL values in SQL. All other variant values remain unchanged.

Syntax

STRIP_NULL_VALUE( <json_doc> )

Required Parameters

• <json_doc>: JSON type, the JSON object to be processed.

Usage Notes

1. If the argument is NULL, returns NULL.
2. If the argument is json null, returns NULL.
3. For json data that is not null, returns the original input.

Examples

0. Prepare data

create table my_test(id, v json) properties('replication_num' = '1');
insert into my_test values(0, 'null'), (1, null), (2, 123), (3, '{"key": 445}'), (4, '{"key": null}');

select * from my_test;

1. Example 1

   select id, v, strip_null_value(v) from my_test order by id;

   +------+--------------+---------------------+
   | id   | v            | strip_null_value(v) |
   +------+--------------+---------------------+
   |    0 | null         | NULL                |
   |    1 | NULL         | NULL                |
   |    2 | 123          | 123                 |
   |    3 | {"key":445}  | {"key":445}         |
   |    4 | {"key":null} | {"key":null}        |
   +------+--------------+---------------------+
   1 row in set (0.02 sec)

2. Example 2

   select
       id
       , v
       , strip_null_value(json_extract(v, '$.key')) 
   from my_test order by id;

   +------+--------------+--------------------------------------------+
   | id   | v            | strip_null_value(json_extract(v, '$.key')) |
   +------+--------------+--------------------------------------------+
   |    0 | null         | NULL                                       |
   |    1 | NULL         | NULL                                       |
   |    2 | 123          | NULL                                       |
   |    3 | {"key":445}  | 445                                        |
   |    4 | {"key":null} | NULL                                       |
   +------+--------------+--------------------------------------------+