Firestore whereEqualsTo from arraylist

Question

I'm trying to list documents that matches field String value from ArrayList.

Simply:

I have ArrayList with tags stored at runtime
and documents with field tag

and I want to query documents that matches tag with one of tags stored in ArrayList. Is this possible with official query or does I have to download all documents and filter it client-side? Thanks for any answers.

Also, this is my method generating query:

public static Query getQueryForFollowed(DocumentSnapshot snapshots) {
    if (snapshots == null || !snapshots.exists()) {
        return FirebaseFirestore.getInstance().collection("posts").whereEqualTo("null", "null"); // return query that will get nothing
    }
    ArrayList<String> f = processFollowedTags(snapshots);
    Query query = FirebaseFirestore.getInstance()
            .collection("posts")
            .whereEqualTo("tag", f.get(0));
    for (int i = 1; i < f.size(); i++) {
        query = query.whereEqualTo("tag", f.get(i));
    }
    return query;
}

I have debugged code and query has contained requested conditions, but query didn't found any document matching it.

Can you share the structure of your db ? – Raj Jun 29 '18 at 15:20 — Raj, Jun 29 '18 at 15:20

score 1 · Answer 1 · answered Jun 29 '18 at 15:27

1

Try This

Query query = FirebaseFirestore.getInstance()
            .collection("posts")
            .whereEqualTo("tag", f.get(0)).orderBy("tag", Query.Direction.ASCENDING);;

answered Jun 29 '18 at 15:27

Raj

2,997
2
12
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com.google.android.gms.tasks.RuntimeExecutionException: com.google.firebase.firestore.FirebaseFirestoreException: INVALID_ARGUMENT: Order by clause cannot contain a field with an equality filter tag – Martin Jun 29 '18 at 15:34

score 0 · Accepted Answer · answered Jun 29 '18 at 15:40

0

After some more search on Google I have found that querying field to multiple values is not available.

According to:

answered Jun 29 '18 at 15:40

Martin

652
9
27

score 0 · Answer 3 · edited Nov 01 '18 at 17:32

0

Below code snippet may help you.

fun arrayContainsQueries() {
    // [START array_contains_filter]
    val citiesRef = db.collection("cities")
    citiesRef.whereArrayContains("regions", "west_coast")
    // [END array_contains_filter]

}

ref : git

edited Nov 01 '18 at 17:32

answered Nov 01 '18 at 15:41

user3103785

1

Sorry, I don't use Kotlin in my app – Martin Nov 01 '18 at 18:12

score 0 · Answer 4 · answered Sep 17 '20 at 01:21

As of Nov 2019 this is now possible to do with the in query.

With the in query, you can query a specific field for multiple values (up to 10) in a single query. You do this by passing a list containing all the values you want to search for, and Cloud Firestore will match any document whose field equals one of those values.

it would look like this:

 Query query = FirebaseFirestore.getInstance()
    .collection("posts")
    .whereIn("tag", f);

Firestore whereEqualsTo from arraylist

4 Answers4