2

I am trying to find a away to SUM the relationship field, but always throw an exception~

So it`s possible to sum a relationship filed by using realm database?

if u knows where i write wrong, please tell me, thanks a lot :)

Assuming I have the following dataset:

public class Service extends RealmObject {
    private String id;
    private RealmList<Service> extras;
    private boolean selected;
    // getters and setters
}

public class ServiceExtra extends RealmObject {
    private String id;
    private float price;
    private boolean selected;
    // getters and setters
}

and then, i guess the query code like this

Realm.getDefaultInstance()
     .where(Service.class)
     .equalTo("selected",true)
     .equalTo("extras.selected",true)
     .sum("extras.price");

but always throw

java.lang.IllegalArgumentException: Field does not exist: extras.price
     at io.realm.RealmObjectSchema.getAndCheckFieldIndex(RealmObjectSchema.java:756)
     at io.realm.RealmQuery.sum(RealmQuery.java:1592)

UPDATE

Realm realm = Realm.getDefaultInstance();
Service service = realm.where(Service.class).equalTo("selected",true).findFirst();
int totalPrice = service.extras.where().equalTo("selected",true).sum("price");

or

Realm realm = Realm.getDefaultInstance();
RealmResult<Service> services = realm.where(Service.class)
            .equalTo("selected",true).finAll();
int totalPrice;
for(Service service : services){
    totalPrice += service.extras.where()
            .equalTo("selected",true).sum("price");
}
lixi
  • 31
  • 4

1 Answers1

1

Try the following to sum, min, max, average field 

RealmResults<User> results = realm.where(User.class).findAll();
 long   sum     = results.sum("age").longValue();
 long   min     = results.min("age").longValue();
 long   max     = results.max("age").longValue();
 double average = results.average("age");

 long   matches = results.size();
Amrutha Saj
  • 1,408
  • 16
  • 35