How to filter null values of FDM view's inherent property in GraphQL

@Mohit Shakaly
myType is a directRelation.  It’s type is defined by a (space, externalId) tuple. 

Apologies for the very delayed reply.   I’m using the null of the externalId as a measure of ‘null’ with respect to the direct relation.

# Based on the following model derived from the Actor/Movie example:


type PersonType @view(space: "test", version: "1") {
    typename: String!
}

interface Person @view(space: "test", version: "1") {
    typename: PersonType
    name: String!
    age: Int
}

#populate your Actors with 'actor' as the PersonType, do not populate the Directors with any typename

# using the following graphQL query, you'll get just 'Director' Persons
query MyQuery {
  listPerson(filter: {typename: {externalId: {isNull: true}}}) {
    items {
      name
      typename {
        typename
      }
    }
  }
}

fyi @Dilini Fernando