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Returns NULL if the input string is a valid JSON document or NULL. Otherwise, returns an error message.

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Syntax

CHECK_JSON(<json_string>)

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Parameters

ParameterDescriptionSupported input types
<json_string>The string to validate as JSON.TEXT

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Return Type

The CHECK_JSON function returns a result of type TEXT.

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Remarks

If you don’t care about the error message, you can also use the JSON_IS_VALID function.

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Examples

Example The following code example validates a simple JSON string: 
SELECT CHECK_JSON('{"name": "John"}');
Returns: NULL The previous code example returns NULL because the input string is valid JSON. Example The following code example validates a simple JSON string: 
SELECT CHECK_JSON('{"name": "John"}{"name": "John"}');
Returns: TAPE_ERROR: The JSON document has an improper structure: missing or superfluous commas, braces, missing keys, etc. The previous code example returns an error message because the input string is invalid JSON as it contains two JSON objects next to each other.