Collection group

Description

Returns all documents from any collection with the specified collection ID, regardless of its parent.

Syntax

Node.js

const results = await db.pipeline()
  .collectionGroup('departments')
  .execute();

Client examples

Web

const results = await execute(db.pipeline()
  .collectionGroup("games")
  .sort(field("name").ascending())
  );
test.firestore.js

Swift
let results = try await db.pipeline()
  .collectionGroup("games")
  .sort([Field("name").ascending()])
  .execute()
PipelineSnippets.swift

Kotlin

val results = db.pipeline()
    .collectionGroup("games")
    .sort(field("name").ascending())
    .execute()
DocSnippets.kt

Java

Task<Pipeline.Snapshot> results = db.pipeline()
    .collectionGroup("games")
    .sort(field("name").ascending())
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

results = (
    client.pipeline()
    .collection_group("games")
    .sort(Field.of("name").ascending())
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot results =
    firestore
        .pipeline()
        .collectionGroup("games")
        .sort(ascending(field("name")))
        .execute()
        .get();
PipelineSnippets.java

Behavior

In order to use the collection_group stage, it must appear as the first stage in the pipeline.

The order of documents returned from the collection_group stage is unstable and shouldn't be relied upon. A subsequent sort stage can be used to obtain a deterministic ordering.

For example, for the following documents:

Node.js

await db.collection('cities/SF/departments').doc('building').set({name: 'SF Building Deparment', employees: 750});
await db.collection('cities/NY/departments').doc('building').set({name: 'NY Building Deparment', employees: 1000});
await db.collection('cities/CHI/departments').doc('building').set({name: 'CHI Building Deparment', employees: 900});
await db.collection('cities/NY/departments').doc('finance').set({name: 'NY Finance Deparment', employees: 1200});

The collection_group stage can be used to return documents from every departments collection across all parent collections in the database.

Node.js

const results = await db.pipeline()
  .collectionGroup('departments')
  .sort(field('employees').ascending())
  .execute();

This query produces the following documents:

  {name: 'SF Building Deparment', employees: 750}
  {name: 'CHI Building Deparment', employees: 900}
  {name: 'NY Building Deparment', employees: 1000}
  {name: 'NY Finance Deparment', employees: 1200}