IS_VALID_JSON function

The IS_VALID_JSON function validates a JSON string. The function returns Boolean true (t) if the string is properly formed JSON or false (f) 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

Example

The following example creates a table and inserts JSON strings for testing.

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]');

The following example validates the strings in the preceding 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         
 2 | {"a":{"b":{"c":1}}} | true         
 4 | {"a": [1,2,"b"]}    | true         
 6 | {{}}                | false        
 8 | {1:"a"}             | false        
10 | [1,2,3]             | false