If any of the parameters are NULL or an empty string, the result is NULL.
If the size of the NVP_string is greater than 16 MB, then the result is NULL.
The function tries to return an appropriately-sized JSON result object with its character set the same as the input NVP_string’s character set. If the result is too large to fit in the JSON result type, a NULL is returned.
You may use the RETURNS clause with this function to specify the size of the JSON object to return. If the result does not fit in the specified JSON object, then a NULL is returned.
The only supported types for the RETURNS clause are JSON(*) CHARACTER SET LATIN and JSON(*) CHARACTER SET UNICODE where * can be any valid size for JSON.
If the input parameters consist of mixed character types, then all the input parameter character types are converted to the RETURNS clause character type if it is specified, or converted to the NVP_string character type.