An aggregation query processes the data from multiple index entries to return a single summary value.
Cloud Firestore supports the following aggregation queries:
-
count() -
sum() -
average()
Cloud Firestore calculates the aggregation and transmits only the result back to your application. Compared to executing a full query and calculating the aggregation in your app, aggregation queries save on both billed document reads and bytes transferred.
Aggregation queries rely on the existing index configuration that your queries already use, and scale proportionally to the number of index entries scanned. Latency increases with the number of items in the aggregation.
Use the count()
aggregation
The count()
aggregation query lets you
determine the number of documents in a collection or query.
For more information about the example data, see Getting data .
The following count()
aggregation returns the total number of cities in the cities
collection.
Web
const coll = collection ( db , "cities" ); const snapshot = await getCountFromServer ( coll ); console . log ( 'count: ' , snapshot . data (). count );
Swift
Note:
This product is not available on watchOS and App Clip targets.
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
Note:
This product is not available on watchOS and App Clip targets.
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
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
The count()
aggregation takes into account any filters on the query and any limit
clauses.
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
Note:
This product is not available on watchOS and App Clip targets.
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
Note:
This product is not available on watchOS and App Clip targets.
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
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
Use the sum()
aggregation
Use the sum()
aggregation to return the total sum of numeric values that
match a given query—for example:
Web
const coll = collection ( firestore , 'cities' ); const snapshot = await getAggregateFromServer ( coll , { totalPopulation : sum ( 'population' ) }); console . log ( 'totalPopulation: ' , snapshot . data (). totalPopulation );
Swift
Note:
This product is not available on watchOS and App Clip targets.
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
Note:
This product is not available on watchOS and App Clip targets.
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
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 }
The sum()
aggregation takes into account any filters on the query and any
limit clauses—for example:
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
Note:
This product is not available on watchOS and App Clip targets.
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
Note:
This product is not available on watchOS and App Clip targets.
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
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 }
Use the average()
aggregation
Use the average()
aggregation to return the average of numeric values that match a
given query, for example:
Web
const coll = collection ( firestore , 'cities' ); const snapshot = await getAggregateFromServer ( coll , { averagePopulation : average ( 'population' ) }); console . log ( 'averagePopulation: ' , snapshot . data (). averagePopulation );
Swift
Note:
This product is not available on watchOS and App Clip targets.
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
Note:
This product is not available on watchOS and App Clip targets.
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
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 }
The average()
aggregation takes into account any filters on the query and any limit
clauses, for example:
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
Note:
This product is not available on watchOS and App Clip targets.
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
Note:
This product is not available on watchOS and App Clip targets.
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
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 }
Calculate multiple aggregations in a query
You can combine multiple aggregations in a single aggregation pipeline. This can reduce the number of index reads required. If the query includes aggregations on multiple fields, the query might requires a composite index. In that case, Cloud Firestore suggests an index.
The following example performs multiple aggregations in a single aggregation query:
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
Note:
This product is not available on watchOS and App Clip targets.
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
Note:
This product is not available on watchOS and App Clip targets.
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
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 } }
Queries with multiple aggregations include only the documents that contain all the fields in each aggregation. This might lead to different results from performing each aggregation separately.
Security rules for aggregation queries
Cloud Firestore Security Rules work the same on aggregation queries as on queries that return documents. In other words, if and only if your rules allow clients to execute certain collection or collection group queries, clients can also perform the aggregation on those queries. Learn more about how Cloud Firestore Security Rules interact with queries .
Behavior and limitations
As you work with aggregation queries, note the following behavior and limitations:
-
You can't use aggregation queries with real-time listeners and offline queries. Aggregation queries are only supported through a direct server response. Queries are served only by the Cloud Firestore backend, skipping the local cache and any buffered updates. This behavior is identical to operations that are performed inside Cloud Firestore transactions .
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If an aggregation can't resolve within 60 seconds, it returns a
DEADLINE_EXCEEDEDerror. Performance depends on your index configuration and on the size of the dataset.If the operation can't be completed within the 60 second deadline, a possible workaround is to use counters for large datasets.
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Aggregation queries read from index entries and include only indexed fields.
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Adding an
OrderByclause to an aggregation query limits the aggregation to the documents where the sorting field exists. -
For
sum()andaverage()aggregations, non-numeric values are ignored.sum()andaverage()aggregations take into account only integer values and floating-point number values. -
When combining multiple aggregations in a single query, note that
sum()andaverage()ignore non-numeric values whilecount()includes non-numeric values. -
If you combine aggregations that are on different fields, the calculation includes only the documents that contain all those fields.
Pricing
Pricing for aggregation queries depends on the number of index entries that the query matches. You are charged a small number of reads for a large number of matched entries. You are charged one read operation for each batch of up to 1000 index entries read.
For more information about aggregation queries pricing, see Aggregation queries .
