Expected results when querying fields - Administrator Guide - Cortex XSIAM - Cortex - Security Operations

If specific fields are stated in the fields stage, those exact fields will be returned. 

If no fields are stated in the query, the xdm_core fieldset will be returned.

Unmapped fields are treated as NULL. An unmapped field is an xdm field that hasn't been mapped from the relevant datasets using a Data Model Rule.

By default, the _time system field will be added to all data model queries. Yet, the _time system field will not be added to queries that contain the comp stage.

For dataset queries, all current system fields will be returned, even if they are not stated in the query.

For UNION between XDM and dataset, each part of the UNION will return its own fields.

Each new column in the result set created by the alter stage will be added as the last column. You can specify a different column order by modifying the field order in the fields stage of the query.

Each new column in the result set created by the comp stage will be added as the last column. Other fields that are not in the group by / calculated column will be removed from the result set, including the core fields and _time system field.

When no limit is explicitly stated in a datamodel query, a maximum of 1000 results are returned (default). When this limit is applied to results using the limit stage, it will be indicated in the user interface.