SOQL FIELDS() Function

FIELDS(ALL) – Select all the fields of an object.
FIELDS(CUSTOM) – Select all the custom fields of an object.
FIELDS(STANDARD) – Select all the standard fields of an object.

In each case, FIELDS() respects field-level security so it only shows the fields that you have permission to access.

FIELDS() is limited to returning 200 records.

FIELDS(ALL) and FIELDS(CUSTOM) are not supported in Apex due to being unbounded, having sets of fields that the API can’t determine in advance.

https://developer.salesforce.com/docs/atlas.en-us.soql_sosl.meta/soql_sosl/sforce_api_calls_soql_select_fields.htm?_ga=2.106773379.1216528802.1671603324-1158522964.1660054937