Resumir datos con consultas de agregación

Una consulta de agregación procesa los datos de varias entradas de índice para devolver un único valor de resumen.

Cloud Firestore admite las siguientes consultas de agregación:

  • count()
  • sum()
  • average()

Cloud Firestore calcula la agregación y transmite solo el resultado a su aplicación. En comparación con ejecutar una consulta completa y calcular la agregación en su aplicación, las consultas de agregación ahorran tanto en lecturas de documentos facturados como en bytes transferidos.

Las consultas de agregación se basan en la configuración de índice existente que sus consultas ya utilizan y escalan proporcionalmente al número de entradas de índice analizadas. La latencia aumenta con la cantidad de elementos de la agregación.

Utilice la agregación count()

La consulta de agregación count() le permite determinar la cantidad de documentos en una colección o consulta.

Consulte los datos de ejemplo que configuramos en Obtención de datos .

La siguiente agregación count() devuelve el número total de ciudades en la colección cities .

Web modular API

const coll = collection(db, "cities");
const snapshot = await getCountFromServer(coll);
console.log('count: ', snapshot.data().count);
count_aggregate_collection.js
Rápido
Nota: Este producto no está disponible en destinos watchOS y App Clip.
let query = db.collection("cities")
let countQuery = query.count
do {
  let snapshot = try await countQuery.getAggregation(source: .server)
  print(snapshot.count)
} catch {
  print(error)
}
ViewController.swift
C objetivo
Nota: Este producto no está disponible en destinos watchOS y App Clip.
FIRCollectionReference *query = [self.db collectionWithPath:@"cities"];
[query.count aggregationWithSource:FIRAggregateSourceServer
                        completion:^(FIRAggregateQuerySnapshot *snapshot,
                                     NSError *error) {
    if (error != nil) {
        NSLog(@"Error fetching count: %@", error);
    } else {
        NSLog(@"Cities count: %@", snapshot.count);
    }
}];
ViewController.m

Java

Query query = db.collection("cities");
AggregateQuery countQuery = query.count();
countQuery.get(AggregateSource.SERVER).addOnCompleteListener(new OnCompleteListener<AggregateQuerySnapshot>() {
    @Override
    public void onComplete(@NonNull Task<AggregateQuerySnapshot> task) {
        if (task.isSuccessful()) {
            // Count fetched successfully
            AggregateQuerySnapshot snapshot = task.getResult();
            Log.d(TAG, "Count: " + snapshot.getCount());
        } else {
            Log.d(TAG, "Count failed: ", task.getException());
        }
    }
});
DocSnippets.java

Kotlin+KTX

val query = db.collection("cities")
val countQuery = query.count()
countQuery.get(AggregateSource.SERVER).addOnCompleteListener { task ->
    if (task.isSuccessful) {
        // Count fetched successfully
        val snapshot = task.result
        Log.d(TAG, "Count: ${snapshot.count}")
    } else {
        Log.d(TAG, "Count failed: ", task.getException())
    }
}
DocSnippets.kt

Dart

// Returns number of documents in users collection
db.collection("users").count().get().then(
      (res) => print(res.count),
      onError: (e) => print("Error completing: $e"),
    );
firestore.dart
Ir
package firestore

import (
	"context"
	"errors"
	"fmt"
	"io"

	"cloud.google.com/go/firestore"
	firestorepb "cloud.google.com/go/firestore/apiv1/firestorepb"
)

func createCountQuery(w io.Writer, projectID string) error {

	// Instantiate the client
	ctx := context.Background()
	client, err := firestore.NewClient(ctx, projectID)
	if err != nil {
		return err
	}
	defer client.Close()

	collection := client.Collection("users")
	query := collection.Where("born", ">", 1850)

	// `alias` argument--"all"--provides a key for accessing the aggregate query
	// results. The alias value must be unique across all aggregation aliases in
	// an aggregation query and must conform to allowed Document field names.
	//
	// See https://cloud.google.com/firestore/docs/reference/rpc/google.firestore.v1#document for details.
	aggregationQuery := query.NewAggregationQuery().WithCount("all")
	results, err := aggregationQuery.Get(ctx)
	if err != nil {
		return err
	}

	count, ok := results["all"]
	if !ok {
		return errors.New("firestore: couldn't get alias for COUNT from results")
	}

	countValue := count.(*firestorepb.Value)
	fmt.Fprintf(w, "Number of results from query: %d\n", countValue.GetIntegerValue())
	return nil
}

aggregate_query_count.go
Java
CollectionReference collection = db.collection("cities");
AggregateQuerySnapshot snapshot = collection.count().get().get();
System.out.println("Count: " + snapshot.getCount());
Nodo.js
const collectionRef = db.collection('cities');
const snapshot = await collectionRef.count().get();
console.log(snapshot.data().count);
Pitón
from google.cloud import firestore
from google.cloud.firestore_v1 import aggregation
from google.cloud.firestore_v1.base_query import FieldFilter


def create_count_query(project_id: str) -> None:
    """Builds an aggregate query that returns the number of results in the query.

    Arguments:
      project_id: your Google Cloud Project ID
    """
    client = firestore.Client(project=project_id)

    collection_ref = client.collection("users")
    query = collection_ref.where(filter=FieldFilter("born", ">", 1800))
    aggregate_query = aggregation.AggregationQuery(query)

    # `alias` to provides a key for accessing the aggregate query results
    aggregate_query.count(alias="all")

    results = aggregate_query.get()
    for result in results:
        print(f"Alias of results from query: {result[0].alias}")
        print(f"Number of results from query: {result[0].value}")


aggregate_query_count.py

La agregación count() tiene en cuenta los filtros de la consulta y las cláusulas limit .

Web modular API

const coll = collection(db, "cities");
const q = query(coll, where("state", "==", "CA"));
const snapshot = await getCountFromServer(q);
console.log('count: ', snapshot.data().count);
count_aggregate_query.js
Rápido
Nota: Este producto no está disponible en destinos watchOS y App Clip.
let query = db.collection("cities").whereField("state", isEqualTo: "CA")
let countQuery = query.count
do {
  let snapshot = try await countQuery.getAggregation(source: .server)
  print(snapshot.count)
} catch {
  print(error)
}
ViewController.swift
C objetivo
Nota: Este producto no está disponible en destinos watchOS y App Clip.
FIRQuery *query =
    [[self.db collectionWithPath:@"cities"]
                 queryWhereField:@"state"
                       isEqualTo:@"CA"];
[query.count aggregationWithSource:FIRAggregateSourceServer
                        completion:^(FIRAggregateQuerySnapshot *snapshot,
                                      NSError *error) {
    if (error != nil) {
        NSLog(@"Error fetching count: %@", error);
    } else {
        NSLog(@"Cities count: %@", snapshot.count);
    }
}];
ViewController.m

Java

Query query = db.collection("cities").whereEqualTo("state", "CA");
AggregateQuery countQuery = query.count();
countQuery.get(AggregateSource.SERVER).addOnCompleteListener(new OnCompleteListener<AggregateQuerySnapshot>() {
    @Override
    public void onComplete(@NonNull Task<AggregateQuerySnapshot> task) {
        if (task.isSuccessful()) {
            // Count fetched successfully
            AggregateQuerySnapshot snapshot = task.getResult();
            Log.d(TAG, "Count: " + snapshot.getCount());
        } else {
            Log.d(TAG, "Count failed: ", task.getException());
        }
    }
});
DocSnippets.java

Kotlin+KTX

val query = db.collection("cities").whereEqualTo("state", "CA")
val countQuery = query.count()
countQuery.get(AggregateSource.SERVER).addOnCompleteListener { task ->
    if (task.isSuccessful) {
        // Count fetched successfully
        val snapshot = task.result
        Log.d(TAG, "Count: ${snapshot.count}")
    } else {
        Log.d(TAG, "Count failed: ", task.getException())
    }
}
DocSnippets.kt

Dart

// This also works with collectionGroup queries.
db.collection("users").where("age", isGreaterThan: 10).count().get().then(
      (res) => print(res.count),
      onError: (e) => print("Error completing: $e"),
    );
firestore.dart
Ir
package firestore

import (
	"context"
	"errors"
	"fmt"
	"io"

	"cloud.google.com/go/firestore"
	firestorepb "cloud.google.com/go/firestore/apiv1/firestorepb"
)

func createCountQuery(w io.Writer, projectID string) error {

	// Instantiate the client
	ctx := context.Background()
	client, err := firestore.NewClient(ctx, projectID)
	if err != nil {
		return err
	}
	defer client.Close()

	collection := client.Collection("users")
	query := collection.Where("born", ">", 1850)

	// `alias` argument--"all"--provides a key for accessing the aggregate query
	// results. The alias value must be unique across all aggregation aliases in
	// an aggregation query and must conform to allowed Document field names.
	//
	// See https://cloud.google.com/firestore/docs/reference/rpc/google.firestore.v1#document for details.
	aggregationQuery := query.NewAggregationQuery().WithCount("all")
	results, err := aggregationQuery.Get(ctx)
	if err != nil {
		return err
	}

	count, ok := results["all"]
	if !ok {
		return errors.New("firestore: couldn't get alias for COUNT from results")
	}

	countValue := count.(*firestorepb.Value)
	fmt.Fprintf(w, "Number of results from query: %d\n", countValue.GetIntegerValue())
	return nil
}

aggregate_query_count.go
Java
CollectionReference collection = db.collection("cities");
Query query = collection.whereEqualTo("state", "CA");
AggregateQuerySnapshot snapshot = query.count().get().get();
System.out.println("Count: " + snapshot.getCount());
Nodo.js
const collectionRef = db.collection('cities');
const query = collectionRef.where('state', '==', 'CA');
const snapshot = await query.count().get();
console.log(snapshot.data().count);
Pitón
from google.cloud import firestore
from google.cloud.firestore_v1 import aggregation
from google.cloud.firestore_v1.base_query import FieldFilter


def create_count_query(project_id: str) -> None:
    """Builds an aggregate query that returns the number of results in the query.

    Arguments:
      project_id: your Google Cloud Project ID
    """
    client = firestore.Client(project=project_id)

    collection_ref = client.collection("users")
    query = collection_ref.where(filter=FieldFilter("born", ">", 1800))
    aggregate_query = aggregation.AggregationQuery(query)

    # `alias` to provides a key for accessing the aggregate query results
    aggregate_query.count(alias="all")

    results = aggregate_query.get()
    for result in results:
        print(f"Alias of results from query: {result[0].alias}")
        print(f"Number of results from query: {result[0].value}")


aggregate_query_count.py

Utilice la agregación sum()

Utilice la agregación sum() para devolver la suma total de valores numéricos que coinciden con una consulta determinada, por ejemplo:

Web modular API

const coll = collection(firestore, 'cities');
const snapshot = await getAggregateFromServer(coll, {
  totalPopulation: sum('population')
});

console.log('totalPopulation: ', snapshot.data().totalPopulation);
Rápido
Nota: Este producto no está disponible en destinos watchOS y App Clip.
let query = db.collection("cities")
let aggregateQuery = query.aggregate([AggregateField.sum("population")])
do {
  let snapshot = try await aggregateQuery.getAggregation(source: .server)
  print(snapshot.get(AggregateField.sum("population")))
} catch {
  print(error)
}
ViewController.swift
C objetivo
Nota: Este producto no está disponible en destinos watchOS y App Clip.
FIRQuery *query = [self.db collectionWithPath:@"cities"];
FIRAggregateQuery *aggregateQuery = [query aggregate:@[
    [FIRAggregateField aggregateFieldForSumOfField:@"population"]]];
[aggregateQuery aggregationWithSource:FIRAggregateSourceServer
                           completion:^(FIRAggregateQuerySnapshot *snapshot,
                                        NSError *error) {
    if (error != nil) {
        NSLog(@"Error fetching aggregate: %@", error);
    } else {
        NSLog(@"Sum: %@", [snapshot valueForAggregateField:[FIRAggregateField aggregateFieldForSumOfField:@"population"]]);
    }
}];
ViewController.m

Java

Query query = db.collection("cities");
AggregateQuery aggregateQuery = query.aggregate(AggregateField.sum("population"));
aggregateQuery.get(AggregateSource.SERVER).addOnCompleteListener(new OnCompleteListener<AggregateQuerySnapshot>() {
    @Override
    public void onComplete(@NonNull Task<AggregateQuerySnapshot> task) {
        if (task.isSuccessful()) {
            // Aggregate fetched successfully
            AggregateQuerySnapshot snapshot = task.getResult();
            Log.d(TAG, "Sum: " + snapshot.get(AggregateField.sum("population")));
        } else {
            Log.d(TAG, "Aggregation failed: ", task.getException());
        }
    }
});
DocSnippets.java

Kotlin+KTX

val query = db.collection("cities")
val aggregateQuery = query.aggregate(AggregateField.sum("population"))
aggregateQuery.get(AggregateSource.SERVER).addOnCompleteListener { task ->
    if (task.isSuccessful) {
        // Aggregate fetched successfully
        val snapshot = task.result
        Log.d(TAG, "Sum: ${snapshot.get(AggregateField.sum("population"))}")
    } else {
        Log.d(TAG, "Aggregate failed: ", task.getException())
    }
}
DocSnippets.kt
Java
collection = db.collection("cities");
snapshot = collection.aggregate(sum("population")).get().get();
System.out.println("Sum: " + snapshot.get(sum("population")));
Nodo.js
const coll = firestore.collection('cities');
const sumAggregateQuery = coll.aggregate({
         totalPopulation: AggregateField.sum('population'),
       });
  
const snapshot = await sumAggregateQuery.get();
console.log('totalPopulation: ', snapshot.data().totalPopulation);
Pitón
collection_ref = client.collection("users")
aggregate_query = aggregation.AggregationQuery(collection_ref)

aggregate_query.sum("coins", alias="sum")

results = aggregate_query.get()
for result in results:
    print(f"Alias of results from query: {result[0].alias}")
    print(f"Sum of results from query: {result[0].value}")
Ir
func createSumQuery(w io.Writer, projectID string) error {
  ctx := context.Background()
  client, err := firestore.NewClient(ctx, projectID)
  if err != nil {
    return err
  }
  defer client.Close()

  collection := client.Collection("users")
  query := collection.Where("born", ">", 1850)

  aggregationQuery := query.NewAggregationQuery().WithSum("coins", "sum_coins")
  results, err := aggregationQuery.Get(ctx)
  if err != nil {
    return err
  }

  sum, ok := results["sum_coins"]
  if !ok {
    return errors.New("firestore: couldn't get alias for SUM from results")
  }

  sumValue := sum.(*firestorepb.Value)
  fmt.Fprintf(w, "Sum of results from query: %d\n", sumValue.GetIntegerValue())
  return nil
}

La agregación sum() tiene en cuenta los filtros de la consulta y las cláusulas de límite, por ejemplo:

Web modular API

const coll = collection(firestore, 'cities');
const q = query(coll, where('capital', '==', true));
const snapshot = await getAggregateFromServer(q, {
  totalPopulation: sum('population')
});

console.log('totalPopulation: ', snapshot.data().totalPopulation);
Rápido
Nota: Este producto no está disponible en destinos watchOS y App Clip.
let query = db.collection("cities").whereField("capital", isEqualTo: true)
let aggregateQuery = query.aggregate([AggregateField.sum("population")])
do {
  let snapshot = try await aggregateQuery.getAggregation(source: .server)
  print(snapshot.get(AggregateField.sum("population")))
} catch {
  print(error)
}
ViewController.swift
C objetivo
Nota: Este producto no está disponible en destinos watchOS y App Clip.
FIRQuery *query = [[self.db collectionWithPath:@"cities"]
                   queryWhereFilter:[FIRFilter filterWhereField:@"capital" isEqualTo:@YES]];
FIRAggregateQuery *aggregateQuery = [query aggregate:@[
    [FIRAggregateField aggregateFieldForSumOfField:@"population"]]];
[aggregateQuery aggregationWithSource:FIRAggregateSourceServer
                           completion:^(FIRAggregateQuerySnapshot *snapshot,
                                        NSError *error) {
    if (error != nil) {
        NSLog(@"Error fetching aggregate: %@", error);
    } else {
        NSLog(@"Sum: %@", [snapshot valueForAggregateField:[FIRAggregateField aggregateFieldForSumOfField:@"population"]]);
    }
}];
ViewController.m

Java

Query query = db.collection("cities").whereEqualTo("capital", true);
AggregateQuery aggregateQuery = query.aggregate(AggregateField.sum("population"));
aggregateQuery.get(AggregateSource.SERVER).addOnCompleteListener(new OnCompleteListener<AggregateQuerySnapshot>() {
    @Override
    public void onComplete(@NonNull Task<AggregateQuerySnapshot> task) {
        if (task.isSuccessful()) {
            // Aggregate fetched successfully
            AggregateQuerySnapshot snapshot = task.getResult();
            Log.d(TAG, "Sum: " + snapshot.get(AggregateField.sum("population")));
        } else {
            Log.d(TAG, "Aggregation failed: ", task.getException());
        }
    }
});
DocSnippets.java

Kotlin+KTX

val query = db.collection("cities").whereEqualTo("capital", true)
val aggregateQuery = query.aggregate(AggregateField.sum("population"))
aggregateQuery.get(AggregateSource.SERVER).addOnCompleteListener { task ->
    if (task.isSuccessful) {
        // Aggregate fetched successfully
        val snapshot = task.result
        Log.d(TAG, "Sum: ${snapshot.get(AggregateField.sum("population"))}")
    } else {
        Log.d(TAG, "Aggregate failed: ", task.getException())
    }
}
DocSnippets.kt
Java
collection = db.collection("cities");
query = collection.whereEqualTo("state", "CA");
snapshot = query.aggregate(sum("population")).get().get();
System.out.println("Sum: " + snapshot.get(sum("population")));
Nodo.js
const coll = firestore.collection('cities');
const q = coll.where("capital", "==", true);
const sumAggregateQuery = q.aggregate({
        totalPopulation: AggregateField.sum('population'),
      });

const snapshot = await sumAggregateQuery.get();
console.log('totalPopulation: ', snapshot.data().totalPopulation);
Pitón
collection_ref = client.collection("users")
query = collection_ref.where(filter=FieldFilter("people", "==", "Matthew"))
aggregate_query = aggregation.AggregationQuery(query)

aggregate_query.sum("coins", alias="sum")

results = aggregate_query.get()
for result in results:
    print(f"Alias of results from query: {result[0].alias}")
    print(f"Sum of results from query: {result[0].value}")
Ir
func createSumQuery(w io.Writer, projectID string) error {
  ctx := context.Background()
  client, err := firestore.NewClient(ctx, projectID)
  if err != nil {
    return err
  }
  defer client.Close()

  collection := client.Collection("users")
  query := collection.Where("born", ">", 1850).Limit(5)

  aggregationQuery := query.NewAggregationQuery().WithSum("coins", "sum_coins")
  results, err := aggregationQuery.Get(ctx)
  if err != nil {
    return err
  }

  sum, ok := results["sum_coins"]
  if !ok {
    return errors.New("firestore: couldn't get alias for SUM from results")
  }

  sumValue := sum.(*firestorepb.Value)
  fmt.Fprintf(w, "Sum of results from query: %d\n", sumValue.GetIntegerValue())
  return nil
}

Utilice la agregación average()

Utilice la agregación average() para devolver el promedio de valores numéricos que coinciden con una consulta determinada, por ejemplo:

Web modular API

const coll = collection(firestore, 'cities');
const snapshot = await getAggregateFromServer(coll, {
  averagePopulation: average('population')
});

console.log('averagePopulation: ', snapshot.data().averagePopulation);
Rápido
Nota: Este producto no está disponible en destinos watchOS y App Clip.
let query = db.collection("cities")
let aggregateQuery = query.aggregate([AggregateField.average("population")])
do {
  let snapshot = try await aggregateQuery.getAggregation(source: .server)
  print(snapshot.get(AggregateField.average("population")))
} catch {
  print(error)
}
ViewController.swift
C objetivo
Nota: Este producto no está disponible en destinos watchOS y App Clip.
FIRQuery *query = [self.db collectionWithPath:@"cities"];
FIRAggregateQuery *aggregateQuery = [query aggregate:@[
    [FIRAggregateField aggregateFieldForAverageOfField:@"population"]]];
[aggregateQuery aggregationWithSource:FIRAggregateSourceServer
                           completion:^(FIRAggregateQuerySnapshot *snapshot,
                                        NSError *error) {
    if (error != nil) {
        NSLog(@"Error fetching aggregate: %@", error);
    } else {
        NSLog(@"Avg: %@", [snapshot valueForAggregateField:[FIRAggregateField aggregateFieldForAverageOfField:@"population"]]);
    }
}];
ViewController.m

Java

Query query = db.collection("cities");
AggregateQuery aggregateQuery = query.aggregate(AggregateField.average("population"));
aggregateQuery.get(AggregateSource.SERVER).addOnCompleteListener(new OnCompleteListener<AggregateQuerySnapshot>() {
    @Override
    public void onComplete(@NonNull Task<AggregateQuerySnapshot> task) {
        if (task.isSuccessful()) {
            // Aggregate fetched successfully
            AggregateQuerySnapshot snapshot = task.getResult();
            Log.d(TAG, "Average: " + snapshot.get(AggregateField.average("population")));
        } else {
            Log.d(TAG, "Aggregation failed: ", task.getException());
        }
    }
});
DocSnippets.java

Kotlin+KTX

val query = db.collection("cities")
val aggregateQuery = query.aggregate(AggregateField.average("population"))
aggregateQuery.get(AggregateSource.SERVER).addOnCompleteListener { task ->
    if (task.isSuccessful) {
        // Aggregate fetched successfully
        val snapshot = task.result
        Log.d(TAG, "Average: ${snapshot.get(AggregateField.average("population"))}")
    } else {
        Log.d(TAG, "Aggregate failed: ", task.getException())
    }
}
DocSnippets.kt
Java
collection = db.collection("cities");
snapshot = collection.aggregate(average("population")).get().get();
System.out.println("Average: " + snapshot.get(average("population")));
Nodo.js
const coll = firestore.collection('cities');
const averageAggregateQuery = coll.aggregate({
        averagePopulation: AggregateField.average('population'),
      });

const snapshot = await averageAggregateQuery.get();
console.log('averagePopulation: ', snapshot.data().averagePopulation);
Pitón
collection_ref = client.collection("users")
aggregate_query = aggregation.AggregationQuery(collection_ref)

aggregate_query.avg("coins", alias="avg")

results = aggregate_query.get()
for result in results:
    print(f"Alias of results from query: {result[0].alias}")
    print(f"Average of results from query: {result[0].value}")
Ir
func createAvgQuery(w io.Writer, projectID string) error {
  ctx := context.Background()
  client, err := firestore.NewClient(ctx, projectID)
  if err != nil {
          return err
  }
  defer client.Close()

  collection := client.Collection("users")
  query := collection.Where("born", ">", 1850)

  aggregationQuery := query.NewAggregationQuery().WithAvg("coins", "avg_coins")
  results, err := aggregationQuery.Get(ctx)
  if err != nil {
    return err
  }

  avg, ok := results["avg_coins"]
  if !ok {
    return errors.New("firestore: couldn't get alias for AVG from results")
  }

  avgValue := avg.(*firestorepb.Value)
  fmt.Fprintf(w, "Avg of results from query: %d\n", avgValue.GetDoubleValue())
  return nil
}

La agregación average() tiene en cuenta los filtros de la consulta y las cláusulas de límite, por ejemplo:

Web modular API

const coll = collection(firestore, 'cities');
const q = query(coll, where('capital', '==', true));
const snapshot = await getAggregateFromServer(q, {
  averagePopulation: average('population')
});

console.log('averagePopulation: ', snapshot.data().averagePopulation);
Rápido
Nota: Este producto no está disponible en destinos watchOS y App Clip.
let query = db.collection("cities").whereField("capital", isEqualTo: true)
let aggregateQuery = query.aggregate([AggregateField.average("population")])
do {
  let snapshot = try await aggregateQuery.getAggregation(source: .server)
  print(snapshot.get(AggregateField.average("population")))
} catch {
  print(error)
}
ViewController.swift
C objetivo
Nota: Este producto no está disponible en destinos watchOS y App Clip.
FIRQuery *query = [[self.db collectionWithPath:@"cities"]
                   queryWhereFilter:[FIRFilter filterWhereField:@"capital" isEqualTo:@YES]];
FIRAggregateQuery *aggregateQuery = [query aggregate:@[
    [FIRAggregateField aggregateFieldForAverageOfField:@"population"]]];
[aggregateQuery aggregationWithSource:FIRAggregateSourceServer
                           completion:^(FIRAggregateQuerySnapshot *snapshot,
                                        NSError *error) {
    if (error != nil) {
        NSLog(@"Error fetching aggregate: %@", error);
    } else {
        NSLog(@"Avg: %@", [snapshot valueForAggregateField:[FIRAggregateField aggregateFieldForAverageOfField:@"population"]]);
    }
}];
ViewController.m

Java

Query query = db.collection("cities").whereEqualTo("capital", true);
AggregateQuery aggregateQuery = query.aggregate(AggregateField.average("population"));
aggregateQuery.get(AggregateSource.SERVER).addOnCompleteListener(new OnCompleteListener<AggregateQuerySnapshot>() {
    @Override
    public void onComplete(@NonNull Task<AggregateQuerySnapshot> task) {
        if (task.isSuccessful()) {
            // Aggregate fetched successfully
            AggregateQuerySnapshot snapshot = task.getResult();
            Log.d(TAG, "Average: " + snapshot.get(AggregateField.average("population")));
        } else {
            Log.d(TAG, "Aggregation failed: ", task.getException());
        }
    }
});
DocSnippets.java

Kotlin+KTX

val query = db.collection("cities").whereEqualTo("capital", true)
val aggregateQuery = query.aggregate(AggregateField.average("population"))
aggregateQuery.get(AggregateSource.SERVER).addOnCompleteListener { task ->
    if (task.isSuccessful) {
        // Aggregate fetched successfully
        val snapshot = task.result
        Log.d(TAG, "Average: ${snapshot.get(AggregateField.average("population"))}")
    } else {
        Log.d(TAG, "Aggregate failed: ", task.getException())
    }
}
DocSnippets.kt
Java
collection = db.collection("cities");
query = collection.whereEqualTo("state", "CA");
snapshot = query.aggregate(average("population")).get().get();
System.out.println("Average: " + snapshot.get(average("population")));
Nodo.js
const coll = firestore.collection('cities');
const q = coll.where("capital", "==", true);
const averageAggregateQuery = q.aggregate({
        averagePopulation: AggregateField.average('population'),
      });

const snapshot = await averageAggregateQuery.get();
console.log('averagePopulation: ', snapshot.data().averagePopulation);
Pitón
collection_ref = client.collection("users")
query = collection_ref.where(filter=FieldFilter("people", "==", "Matthew"))
aggregate_query = aggregation.AggregationQuery(query)

aggregate_query.avg("coins", alias="avg")

results = aggregate_query.get()
for result in results:
    print(f"Alias of results from query: {result[0].alias}")
    print(f"Average of results from query: {result[0].value}")
Ir
func createAvgQuery(w io.Writer, projectID string) error {
  ctx := context.Background()
  client, err := firestore.NewClient(ctx, projectID)
  if err != nil {
        return err
  }
  defer client.Close()

  collection := client.Collection("users")
  query := collection.Where("born", ">", 1850).Limit(5)

  aggregationQuery := query.NewAggregationQuery().WithAvg("coins", "avg_coins")
  results, err := aggregationQuery.Get(ctx)
  if err != nil {
    return err
  }

  avg, ok := results["avg_coins"]
  if !ok {
    return errors.New("firestore: couldn't get alias for AVG from results")
  }

  avgValue := avg.(*firestorepb.Value)
  fmt.Fprintf(w, "Avg of results from query: %d\n", avgValue.GetDoubleValue())
  return nil
}

Calcular múltiples agregaciones en una consulta

Puede combinar varias agregaciones en un único canal de agregación. Esto puede reducir la cantidad de lecturas de índice necesarias. Si la consulta incluye agregaciones en varios campos, es posible que requiera un índice compuesto. En ese caso, Cloud Firestore sugiere un índice.

El siguiente ejemplo realiza múltiples agregaciones en una única consulta de agregación:

Web modular API

const coll = collection(firestore, 'cities');
const snapshot = await getAggregateFromServer(coll, {
  countOfDocs: count(),
  totalPopulation: sum('population'),
  averagePopulation: average('population')
});

console.log('countOfDocs: ', snapshot.data().countOfDocs);
console.log('totalPopulation: ', snapshot.data().totalPopulation);
console.log('averagePopulation: ', snapshot.data().averagePopulation);
Rápido
Nota: Este producto no está disponible en destinos watchOS y App Clip.
let query = db.collection("cities")
let aggregateQuery = query.aggregate([
  AggregateField.count(),
  AggregateField.sum("population"),
  AggregateField.average("population")])
do {
  let snapshot = try await aggregateQuery.getAggregation(source: .server)
  print("Count: \(snapshot.get(AggregateField.count()))")
  print("Sum: \(snapshot.get(AggregateField.sum("population")))")
  print("Average: \(snapshot.get(AggregateField.average("population")))")
} catch {
  print(error)
}
ViewController.swift
C objetivo
Nota: Este producto no está disponible en destinos watchOS y App Clip.
FIRQuery *query = [self.db collectionWithPath:@"cities"];
FIRAggregateQuery *aggregateQuery = [query aggregate:@[
    [FIRAggregateField aggregateFieldForCount],
    [FIRAggregateField aggregateFieldForSumOfField:@"population"],
    [FIRAggregateField aggregateFieldForAverageOfField:@"population"]]];
[aggregateQuery aggregationWithSource:FIRAggregateSourceServer
                           completion:^(FIRAggregateQuerySnapshot *snapshot,
                                        NSError *error) {
    if (error != nil) {
        NSLog(@"Error fetching aggregate: %@", error);
    } else {
        NSLog(@"Count: %@", [snapshot valueForAggregateField:[FIRAggregateField aggregateFieldForCount]]);
        NSLog(@"Sum: %@", [snapshot valueForAggregateField:[FIRAggregateField aggregateFieldForSumOfField:@"population"]]);
        NSLog(@"Avg: %@", [snapshot valueForAggregateField:[FIRAggregateField aggregateFieldForAverageOfField:@"population"]]);
    }
}];
ViewController.m

Java

Query query = db.collection("cities");
AggregateQuery aggregateQuery = query.aggregate(
        AggregateField.count(),
        AggregateField.sum("population"),
        AggregateField.average("population"));
aggregateQuery.get(AggregateSource.SERVER).addOnCompleteListener(new OnCompleteListener<AggregateQuerySnapshot>() {
    @Override
    public void onComplete(@NonNull Task<AggregateQuerySnapshot> task) {
        if (task.isSuccessful()) {
            // Aggregate fetched successfully
            AggregateQuerySnapshot snapshot = task.getResult();
            Log.d(TAG, "Count: " + snapshot.get(AggregateField.count()));
            Log.d(TAG, "Sum: " + snapshot.get(AggregateField.sum("population")));
            Log.d(TAG, "Average: " + snapshot.get(AggregateField.average("population")));
        } else {
            Log.d(TAG, "Aggregation failed: ", task.getException());
        }
    }
});
DocSnippets.java

Kotlin+KTX

val query = db.collection("cities")
val aggregateQuery = query.aggregate(
    AggregateField.count(),
    AggregateField.sum("population"),
    AggregateField.average("population")
)
aggregateQuery.get(AggregateSource.SERVER).addOnCompleteListener { task ->
    if (task.isSuccessful) {
        // Aggregate fetched successfully
        val snapshot = task.result
        Log.d(TAG, "Count: ${snapshot.get(AggregateField.count())}")
        Log.d(TAG, "Sum: ${snapshot.get(AggregateField.sum("population"))}")
        Log.d(TAG, "Average: ${snapshot.get(AggregateField.average("population"))}")
    } else {
        Log.d(TAG, "Aggregate failed: ", task.getException())
    }
}
DocSnippets.kt
Java
collection = db.collection("cities");
query = collection.whereEqualTo("state", "CA");
AggregateQuery aggregateQuery = query.aggregate(count(), sum("population"), average("population"));
snapshot = aggregateQuery.get().get();
System.out.println("Count: " + snapshot.getCount());
System.out.println("Sum: " + snapshot.get(sum("population")));
System.out.println("Average: " + snapshot.get(average("population")));
Nodo.js
const coll = firestore.collection('cities');
const aggregateQuery = coll.aggregate({
    countOfDocs: AggregateField.count(),
    totalPopulation: AggregateField.sum('population'),
    averagePopulation: AggregateField.average('population')
  });

const snapshot = await aggregateQuery.get();
console.log('countOfDocs: ', snapshot.data().countOfDocs);
console.log('totalPopulation: ', snapshot.data().totalPopulation);
console.log('averagePopulation: ', snapshot.data().averagePopulation);
Pitón
collection_ref = client.collection("users")
query = collection_ref.where(filter=FieldFilter("people", "==", "Matthew"))
aggregate_query = aggregation.AggregationQuery(query)

aggregate_query.sum("coins", alias="sum").avg("coins", alias="avg")

results = aggregate_query.get()
for result in results:
    print(f"Alias of results from query: {result[0].alias}")
    print(f"Aggregation of results from query: {result[0].value}")
Ir
func createMultiAggregationQuery(w io.Writer, projectID string) error {
  ctx := context.Background()
  client, err := firestore.NewClient(ctx, projectID)
  if err != nil {
    return err
  }
  defer client.Close()

  collection := client.Collection("users")
  query := collection.Where("born", ">", 1850)

  aggregationQuery := query.NewAggregationQuery().WithCount("count").WithSum("coins", "sum_coins").WithAvg("coins", "avg_coins")
  results, err := aggregationQuery.Get(ctx)
  if err != nil {
    return err
  }
}

Las consultas con múltiples agregaciones incluyen solo los documentos que contienen todos los campos en cada agregación. Esto podría dar lugar a resultados diferentes al realizar cada agregación por separado.

Reglas de seguridad para consultas de agregación

Las reglas de seguridad de Cloud Firestore funcionan igual en consultas de agregación que en consultas que devuelven documentos. En otras palabras, si y sólo si sus reglas permiten a los clientes ejecutar determinadas consultas de colección o de grupo de colecciones, los clientes también pueden realizar la agregación de esas consultas. Obtenga más información sobre cómo interactúan las reglas de seguridad de Cloud Firestore con las consultas .

Comportamiento y limitaciones

Al trabajar con consultas de agregación, tenga en cuenta el siguiente comportamiento y limitaciones:

  • No puede utilizar consultas de agregación con escuchas en tiempo real y consultas sin conexión. Las consultas de agregación solo se admiten mediante respuesta directa del servidor. Las consultas son atendidas únicamente por el backend de Cloud Firestore, omitiendo el caché local y las actualizaciones almacenadas en el búfer. Este comportamiento es idéntico a las operaciones realizadas dentro de las transacciones de Cloud Firestore .

  • Si una agregación no se puede resolver en 60 segundos, devuelve un error DEADLINE_EXCEEDED . El rendimiento depende de la configuración de su índice y del tamaño del conjunto de datos.

    Si la operación no se puede completar dentro del plazo de 60 segundos, una posible solución es utilizar contadores para grandes conjuntos de datos.

  • Las consultas de agregación leen de las entradas del índice e incluyen solo campos indexados.

  • Agregar una cláusula OrderBy a una consulta de agregación limita la agregación a los documentos donde existe el campo de clasificación.

  • Para las agregaciones sum() y average() , los valores no numéricos se ignoran. Las agregaciones sum() y average() tienen en cuenta sólo valores enteros y valores numéricos de punto flotante.

  • Al combinar varias agregaciones en una sola consulta, tenga en cuenta que sum() y average() ignoran los valores no numéricos, mientras que count() incluye valores no numéricos.

  • Si combina agregaciones que se encuentran en diferentes campos, el cálculo incluye solo los documentos que contienen todos esos campos.

Precios

El precio de las consultas de agregaciones depende del número de entradas de índice que coinciden con la consulta. Se le cobra una pequeña cantidad de lecturas por una gran cantidad de entradas coincidentes.

Ver información de precios más detallada.