TRY_FROM_JSON

Overview

Parses a JSON string into a specified structured type (STRUCT, ARRAY, MAP, etc.). When parsing fails, it does not throw an error — instead it fills the result with NULL values and includes an error message. This makes it suitable for handling JSON data with uncertain formatting.

Difference from FROM_JSON: FROM_JSON throws an error on parse failure; TRY_FROM_JSON returns a result with an _error_msg field on failure.

Syntax

TRY_FROM_JSON(<json_str>, <type_str>)

Parameters

• <json_str>: STRING type. The JSON string to parse.
• <type_str>: STRING type. The target type description, such as 'STRUCT<a:INT>' or 'ARRAY<STRING>'.

Examples

-- Successful parse: returns the struct, _error_msg is empty SELECT try_from_json('{"a":1}', 'STRUCT<a:INT>'); -- {"a":1,"_error_msg":""} -- Failed parse: returns the struct with NULL field values, _error_msg contains error details SELECT try_from_json('invalid', 'STRUCT<a:INT>'); -- {"a":null,"_error_msg":"failed to parse json | BAD_FIELD | error position `invalid`"} -- Extract a specific field SELECT (try_from_json('{"a":1}', 'STRUCT<a:INT>')).a AS val; -- 1

Related Documentation

• FROM_JSON — version that throws an error on parse failure
• PARSE_JSON