Add input_format_json_empty_as_default setting to treat empty JSON fields as defaults

Why it matters

This feature addresses the issue where empty fields in JSON inputs were not interpreted as default values, potentially causing errors or unexpected behavior during data ingestion. By enabling this setting, users can ensure that empty JSON fields are automatically converted to default column values, improving data import robustness and reducing the need for manual data preprocessing.

How to use it

To use this feature, enable the setting by adding input_format_json_empty_as_default = 1 in your query settings or configuration. For example:

SET input_format_json_empty_as_default = 1;

This will cause empty fields in JSON input data to be treated as default values during insertion.