How to get value of some field in firebase firestore android?

Question

Like upper question, i want to get value of some field in firebase firestore instead of all document with DocumentSnapshot

like this in SQL SE

Answer 1

The Cloud Firestore client-side SDKs always read and returns full documents. There is no way to read a subset of the fields in a document.

You can retrieve the entire document, and then process the DocumentSnapshot to just use the fields you're interested. But this means you're using more bandwidth than needed. If this is a regular occurrence for your app, consider creating a secondary collection where each document contains just the fields you're interested in.