FirebaseFirestore Framework Reference

FIRAggregateField

@interface FIRAggregateField : NSObject

Represents an aggregation that can be performed by Firestore.

• +aggregateFieldForCount

  Create an AggregateField object that can be used to compute the count of documents in the result set of a query.

  The result of a count operation will always be a 64-bit integer value.

  Declaration

  Objective-C

  + (nonnull instancetype)aggregateFieldForCount;

  Return Value

  AggregateField object that can be used to compute the count of documents in the result set of a query.

• +aggregateFieldForSumOfField:

  Create an AggregateField object that can be used to compute the sum of a specified field over a range of documents in the result set of a query.

  The result of a sum operation will always be a 64-bit integer value, a double, or NaN.

  • Summing over zero documents or fields will result in 0L.
  • Summing over NaN will result in a double value representing NaN.
  • A sum that overflows the maximum representable 64-bit integer value will result in a double return value. This may result in lost precision of the result.

  • A sum that overflows the maximum representable double value will result in a double return value representing infinity.

  Declaration

  Objective-C

  + (nonnull instancetype)aggregateFieldForSumOfField:(nonnull NSString *)field;

  Parameters

  field

  Specifies the field to sum across the result set.

  Return Value

  AggregateField object that can be used to compute the sum of a specified field over a range of documents in the result set of a query.

• +aggregateFieldForSumOfFieldPath:

  Create an AggregateField object that can be used to compute the sum of a specified field over a range of documents in the result set of a query.

  The result of a sum operation will always be a 64-bit integer value, a double, or NaN.

  • Summing over zero documents or fields will result in 0L.
  • Summing over NaN will result in a double value representing NaN.
  • A sum that overflows the maximum representable 64-bit integer value will result in a double return value. This may result in lost precision of the result.

  • A sum that overflows the maximum representable double value will result in a double return value representing infinity.

  Declaration

  Objective-C

  + (nonnull instancetype)aggregateFieldForSumOfFieldPath:
      (nonnull FIRFieldPath *)fieldPath;

  Parameters

  fieldPath

  Specifies the field to sum across the result set.

  Return Value

  AggregateField object that can be used to compute the sum of a specified field over a range of documents in the result set of a query.

• +aggregateFieldForAverageOfField:

  Create an AggregateField object that can be used to compute the average of a specified field over a range of documents in the result set of a query.

  The result of an average operation will always be a double or NaN.

  • Averaging over zero documents or fields will result in a double value representing NaN.

  • Averaging over NaN will result in a double value representing NaN.

  Declaration

  Objective-C

  + (nonnull instancetype)aggregateFieldForAverageOfField:
      (nonnull NSString *)field;

  Parameters

  field

  Specifies the field to average across the result set.

  Return Value

  AggregateField object that can be used to compute the average of a specified field over a range of documents in the result set of a query.

• +aggregateFieldForAverageOfFieldPath:

  Create an AggregateField object that can be used to compute the average of a specified field over a range of documents in the result set of a query.

  The result of an average operation will always be a double or NaN.

  • Averaging over zero documents or fields will result in a double value representing NaN.

  • Averaging over NaN will result in a double value representing NaN.

  Declaration

  Objective-C

  + (nonnull instancetype)aggregateFieldForAverageOfFieldPath:
      (nonnull FIRFieldPath *)fieldPath;

  Parameters

  fieldPath

  Specifies the field to average across the result set.

  Return Value

  AggregateField object that can be used to compute the average of a specified field over a range of documents in the result set of a query.