The subfield property requests a minimum set of fields to return values for, by restricting the set of fields for which values are returned you can optimize the performance of the query when using a query filter. Additional values may be returned for fields that the query requires (e.g., ObjectID or Shape fields). Fields not included in the subfields list or required by the query are still present in the rows returned, but are not populated with values. Including all of the fields in the row ensures that the field index position is constant no matter how it was hydrated.
The default setting for subfields is to request values to be returned for all fields. The strings of "*" or "" can be set to return the query to this default. The default of returning all fields should always be used if the intent of the operation is to alter the values of the row and store it.
To set the subfields property to request the values to be returned for the "Name" and "Age" fields a string of "Name, Age" should be provided (white space is optional).
It is not required to set the subfields property if the query filter is to be used in a context where no rows are returned (e.g., Table.Select).
Target Platforms: Windows 10, Windows 8.1