How to query with multiple conditions in Firebase Realtime Database

Question

I need to query something like this:

Select 20 users where (age is from 20 to 30) and (weight is from 50 to 80)

What is the most efficient way to achieve this in Firebase Realtime Database (for Unity)? Assuming "users" table has millions of records.

Any help is much appreciated!

You can first orderbyage ten startAt 20 endat30 then orderby weight theb start at50 endat80, but i don't think it's the most efficient way — mariusz_latarnik01, Mar 21 '18 at 08:49
You cannot add multiple where conditions in firebase. You have to fetch data using startAt and endAt separately and put your login in client side code. — Himanshu, Mar 21 '18 at 08:51
For better performance you can specify your own indexing with .indexOn — mariusz_latarnik01, Mar 21 '18 at 08:56

score 0 · Answer 1 · answered Mar 21 '18 at 09:23

I'm not sure there is a way to achieve this goal without rethinking the data structure.

What I would do if I were in design phase and I needed to query by tens of age is to put inside the user node a structure like this:

"userId": {
    ...
    "ageAndWeightFilter": {
        "20s": <weight>
    }
}

In this way you can query by range of weight and specifically a specific range of 10 years.

1 Answers1