AWS Amplify GraphQL Query For Null Connections - amazon-web-services

Question

I have the following in my schema for my AWS Amplify project:
type DriveTime #model
#auth( rules: [
{allow: groups, groups: ["Admin", "Instructor"]},
{ allow: private, provider: iam }
]) {
id: ID!
start: AWSDateTime!
end: AWSDateTime!
openRegistration: AWSDateTime!
closeRegistration: AWSDateTime!
vehicle: Vehicle #connection(name: "VehicleDriveConnection")
instructor: Instructor #connection(name: "InstructorDriveConnection") #aws_cognito_user_pools #aws_iam
student: Student #connection(name: "StudentDriveConnection")
evaluation: DriveEvaluation #connection(name: "DriveEvaluationConnection")
}
I want to be able to list all drive times where the student connection is empty or null. I am able to get all driveTimes for a single student but not all driveTimes where there is no student.
Since I dont want students to be able to access drive times that are either not open for registration or already registered to another student I have added this to my schema:
type AvailableDriveTime {
id: ID!
start: AWSDateTime!
end: AWSDateTime!
openRegistration: AWSDateTime!
closeRegistration: AWSDateTime!
instructorFirstName: String!
instructorLastName: String!
}
type Query {
listAvailableDriveTimes(limit: Int, nextToken: String): AvailableDriveTimesConnection #function(name: "listAvailableDriveTimes-${env}") #aws_cognito_user_pools #aws_iam
}
And this is my current query in the Lambda resolver:
let currentDate = new Date();
const listDrives = `query ListDrives($limit: Int, $nextToken: String) {
listDriveTimes(limit: $limit, nextToken: $nextToken, filter: {and: {openRegistration: {le: "${currentDate.toISOString()}"}, closeRegistration: {ge: "${currentDate.toISOString()}"}}}) {
items {
id
start
end
openRegistration
closeRegistration
instructor {
firstName
lastName
}
student {
username
}
}
nextToken
}
}`
My current solution is sorting in the lambda resolver then returning the right data but it seems like there has to be a more efficient way.