IS_VALID_JSON function

Note

CAN_JSON_PARSE and its associated functions parse JSON values as SUPER, which Amazon Redshift parses more efficiently than VARCHAR.

Instead of using IS_VALID_JSON, we recommend that you validate your JSON strings using the CAN_JSON_PARSE function.

The IS_VALID_JSON function validates a JSON string. The function returns Boolean true if the string is properly formed JSON or false if the string is malformed. To validate a JSON array, use IS_VALID_JSON_ARRAY function

For more information, see JSON functions.

Syntax

IS_VALID_JSON('json_string')

Arguments

json_string

A string or expression that evaluates to a JSON string.

Return type

BOOLEAN

Examples

To create a table and insert JSON strings for testing, use the following example.

CREATE TABLE test_json(id int IDENTITY(0,1), json_strings VARCHAR);

-- Insert valid JSON strings --
INSERT INTO test_json(json_strings) VALUES
('{"a":2}'), 
('{"a":{"b":{"c":1}}}'), 
('{"a": [1,2,"b"]}');

-- Insert invalid JSON strings --
INSERT INTO test_json(json_strings) VALUES
('{{}}'), 
('{1:"a"}'), 
('[1,2,3]');

To validate the strings in the preceding example, use the following example.

SELECT id, json_strings, IS_VALID_JSON(json_strings) 
FROM test_json
ORDER BY id;

+----+---------------------+---------------+
| id |    json_strings     | is_valid_json |
+----+---------------------+---------------+
|  0 | {"a":2}             | true          |
|  4 | {"a":{"b":{"c":1}}} | true          |
|  8 | {"a": [1,2,"b"]}    | true          |
| 12 | {{}}                | false         |
| 16 | {1:"a"}             | false         |
| 20 | [1,2,3]             | false         |
+----+---------------------+---------------+