Toplama sorgusu, tek bir özet değeri döndürmek için birden fazla dizin girişindeki verileri işler.
Cloud Firestore, aşağıdaki toplama sorgularını destekler:
count()
sum()
average()
Cloud Firestore toplamayı hesaplar ve yalnızca sonucu uygulamanıza iletir. Toplam sorgu yürütmeye ve uygulamanızda toplamayı hesaplamaya kıyasla toplama sorguları, hem faturalandırılan belge okumalarda hem de aktarılan baytlarda tasarruf sağlar.
Toplama sorguları, sorgularınızın halihazırda kullandığı mevcut dizin yapılandırmasını kullanır ve taranan dizin girişlerinin sayısına göre ölçeklendirilir. Gecikme, toplamadaki öğe sayısıyla birlikte artar.
count()
toplama işlevini kullanma
count()
toplama sorgusu, bir koleksiyondaki veya sorgudaki doküman sayısını belirlemenize olanak tanır.
Örnek veriler hakkında daha fazla bilgi için Veri alma başlıklı makaleyi inceleyin.
Aşağıdaki count()
toplama işlemi, cities
koleksiyonundaki toplam şehir sayısını döndürür.
Web
const coll = collection(db, "cities"); const snapshot = await getCountFromServer(coll); console.log('count: ', snapshot.data().count);
Swift
let query = db.collection("cities") let countQuery = query.count do { let snapshot = try await countQuery.getAggregation(source: .server) print(snapshot.count) } catch { print(error) }
Objective-C
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); } }];
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()); } } });
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()) } }
Dart
// Returns number of documents in users collection db.collection("cities").count().get().then( (res) => print(res.count), onError: (e) => print("Error completing: $e"), );
Go
Java
CollectionReference collection = db.collection("cities"); AggregateQuerySnapshot snapshot = collection.count().get().get(); System.out.println("Count: " + snapshot.getCount());
Node.js
const collectionRef = db.collection('cities'); const snapshot = await collectionRef.count().get(); console.log(snapshot.data().count);
Python
count()
toplama işlemi, sorgudaki tüm filtreleri ve limit
yan tümcelerini dikkate alır.
Web
const coll = collection(db, "cities"); const q = query(coll, where("state", "==", "CA")); const snapshot = await getCountFromServer(q); console.log('count: ', snapshot.data().count);
Swift
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) }
Objective-C
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); } }];
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()); } } });
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()) } }
Dart
// This also works with collection queries. db.collection("cities").where("capital", isEqualTo: 10).count().get().then( (res) => print(res.count), onError: (e) => print("Error completing: $e"), );
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());
Node.js
const collectionRef = db.collection('cities'); const query = collectionRef.where('state', '==', 'CA'); const snapshot = await query.count().get(); console.log(snapshot.data().count);
Python
sum()
toplama işlevini kullanma
Belirli bir sorguyla eşleşen sayısal değerlerin toplamını döndürmek için sum()
toplamasını kullanın. Örneğin:
Web
const coll = collection(firestore, 'cities'); const snapshot = await getAggregateFromServer(coll, { totalPopulation: sum('population') }); console.log('totalPopulation: ', snapshot.data().totalPopulation);
Swift
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) }
Objective-C
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"]]); } }];
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()); } } });
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()) } }
Dart
db.collection("cities").aggregate(sum("population")).get().then( (res) => print(res.getAverage("population")), onError: (e) => print("Error completing: $e"), );
Java
collection = db.collection("cities"); snapshot = collection.aggregate(sum("population")).get().get(); System.out.println("Sum: " + snapshot.get(sum("population")));
Node.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);
Python
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}")
Go
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 }
sum()
toplama işlemi, sorgudaki tüm filtreleri ve sınırlama yan tümcelerini dikkate alır. Örneğin:
Web
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);
Swift
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) }
Objective-C
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"]]); } }];
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()); } } });
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()) } }
Dart
db .collection("cities") .where("capital", isEqualTo: true) .aggregate(sum("population")) .get() .then( (res) => print(res.getAverage("population")), onError: (e) => print("Error completing: $e"), );
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")));
Node.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);
Python
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}")
Go
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 }
average()
toplama işlevini kullanma
Belirli bir sorguyla eşleşen sayısal değerlerin ortalamasını döndürmek için average()
toplamasını kullanın. Örneğin:
Web
const coll = collection(firestore, 'cities'); const snapshot = await getAggregateFromServer(coll, { averagePopulation: average('population') }); console.log('averagePopulation: ', snapshot.data().averagePopulation);
Swift
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) }
Objective-C
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"]]); } }];
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()); } } });
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()) } }
Dart
db.collection("cities").aggregate(average("population")).get().then( (res) => print(res.getAverage("population")), onError: (e) => print("Error completing: $e"), );
Java
collection = db.collection("cities"); snapshot = collection.aggregate(average("population")).get().get(); System.out.println("Average: " + snapshot.get(average("population")));
Node.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);
Python
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}")
Go
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 }
average()
toplama işlemi, sorgudaki tüm filtreleri ve sınırlama yan tümcelerini dikkate alır. Örneğin:
Web
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);
Swift
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) }
Objective-C
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"]]); } }];
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()); } } });
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()) } }
Dart
db .collection("cities") .where("capital", isEqualTo: true) .aggregate(average("population")) .get() .then( (res) => print(res.getAverage("population")), onError: (e) => print("Error completing: $e"), );
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")));
Node.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);
Python
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}")
Go
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 }
Sorguda birden fazla toplama işlemini hesaplama
Birden fazla toplama işlemini tek bir toplama ardışık düzeninde birleştirebilirsiniz. Bu, gereken dizin okumalarının sayısını azaltabilir. Sorgu birden fazla alanda toplama içeriyorsa sorgu için birleşik dizin gerekebilir. Bu durumda, Cloud Firestore bir dizin önerir.
Aşağıdaki örnek, tek bir toplama sorgusunda birden çok toplama işlemi gerçekleştirmektedir:
Web
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);
Swift
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) }
Objective-C
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"]]); } }];
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()); } } });
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()) } }
Dart
db .collection("cities") .aggregate( count(), sum("population"), average("population"), ) .get() .then( (res) { print(res.count); print(res.getSum("population")); print(res.getAverage("population")); }, onError: (e) => print("Error completing: $e"), );
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")));
Node.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);
Python
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}")
Go
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 } }
Birden fazla toplama içeren sorgular yalnızca her toplamadaki tüm alanları içeren dokümanları içerir. Bu, her toplamayı ayrı ayrı gerçekleştirmekten farklı sonuçlara yol açabilir.
Toplama sorguları için güvenlik kuralları
Cloud Firestore Security Rules, toplama sorgularında doküman döndüren sorgularla aynı şekilde çalışır. Diğer bir deyişle, istemciler yalnızca kurallarınız belirli koleksiyon veya koleksiyon grubu sorgularını yürütmelerine izin veriyorsa bu sorgularda toplama işlemini de gerçekleştirebilir. Cloud Firestore Security Rules'un sorgularla nasıl etkileşimde bulunduğu hakkında daha fazla bilgi edinin.
Davranış ve sınırlamalar
Toplama sorgularıyla çalışırken aşağıdaki davranış ve sınırlamalara dikkat edin:
Toplama sorgularını gerçek zamanlı dinleyiciler ve çevrimdışı sorgularla kullanamazsınız. Toplama sorguları yalnızca doğrudan sunucu yanıtı aracılığıyla desteklenir. Sorgular, yerel önbellek ve arabelleğe alınan güncellemeler atlanarak yalnızca Cloud Firestore arka ucu tarafından sunulur. Bu davranış, Cloud Firestore işlemleri içinde gerçekleştirilen işlemlerle aynıdır.
Bir toplama işlemi 60 saniye içinde çözülemezse
DEADLINE_EXCEEDED
hatası döndürülür. Performans, dizin yapılandırmanıza ve veri kümesinin boyutuna bağlıdır.İşlem 60 saniyelik son tarih içinde tamamlanamazsa büyük veri kümeleri için sayaçlar kullanmak olası bir geçici çözümdür.
Toplama sorguları, dizin girişlerinden okunur ve yalnızca dizine eklenen alanları içerir.
Toplama sorgusuna
OrderBy
ifadesi eklediğinizde toplama işlemi, sıralama alanının bulunduğu belgelerle sınırlandırılır.sum()
veaverage()
toplamalarında sayısal olmayan değerler yoksayılır.sum()
veaverage()
toplamaları yalnızca tam sayı ve kayan noktalı sayı değerlerini dikkate alır.Tek bir sorguda birden fazla toplama işlemini birleştirirken
sum()
veaverage()
'ün sayısal olmayan değerleri yoksaydığını,count()
'nin ise sayısal olmayan değerleri içerdiğini unutmayın.Farklı alanlarda bulunan toplama işlemlerini birleştirirseniz hesaplama yalnızca tüm bu alanları içeren dokümanları içerir.
Fiyatlandırma
Toplama sorgularının fiyatlandırması, sorgunun eşleştiği dizin girişlerinin sayısına bağlıdır. Çok sayıda eşleşen giriş için az sayıda okuma ücreti ödersiniz. Okunan 1.000'e kadar dizin girişi içeren her toplu iş için bir okuma işlemi ücreti alınır.
Toplama sorgularının fiyatlandırması hakkında daha fazla bilgi için Toplama sorguları başlıklı makaleyi inceleyin.