In Looker, how does a user add a field to a set?

In Looker, adding a field to a set involves specifying the field directly within the set declaration. This method allows developers to define the precise fields they want to include in the set and to ensure the set aligns with the desired functionality or analysis. By declaring the field in the set, developers can manipulate its behavior, such as applying aggregations or filters, making this approach both straightforward and effective.

In contrast, using the add() function is not a standard way to include fields in a set, as this function is typically used in different contexts in Looker. Referencing a field's name directly does not result in adding it to a set unless it is properly included in the declaration. Implementing a join is more about establishing relationships between different tables rather than specifically adding fields to a set. Therefore, specifying the field in the set declaration is the correct method for including it in a set within Looker.