Class StdDevSAggregator<V extends Number>

java.lang.Object

org.apache.derby.impl.sql.execute.VarPAggregator<V>

org.apache.derby.impl.sql.execute.VarSAggregator<V>

org.apache.derby.impl.sql.execute.StdDevSAggregator<V>

All Implemented Interfaces:

Externalizable, Serializable, Aggregator<V, Double, VarPAggregator<V>>

public class StdDevSAggregator<V extends Number>
extends VarSAggregator<V>

This class implements the SQL Standard STDDEV_SAMP() aggregator, computing a sample's standard deviation. It relies on VarSAggregator to compute the sample's variance and then applies the textbook definition of standard deviation:

√var_samp()

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class VarPAggregator

VarPAggregator.Sums

Field Summary

Fields

Modifier and Type	Field	Description
private static final long	serialVersionUID

Fields inherited from class VarPAggregator

count, sums

Constructor Summary

Constructors

Constructor	Description
StdDevSAggregator()

Method Summary

Modifier and Type	Method	Description
Double	terminate()	Return the result scalar value

Methods inherited from class VarSAggregator

computeVar

Methods inherited from class VarPAggregator

accumulate, init, merge, readExternal, writeExternal

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

serialVersionUID

private static final long serialVersionUID

See Also:

• Constant Field Values

Constructor Details

StdDevSAggregator

public StdDevSAggregator()

Method Details

terminate

public Double terminate()

Description copied from interface: Aggregator

Return the result scalar value

Specified by:

terminate in interface Aggregator<V extends Number, Double, VarPAggregator<V extends Number>>

Overrides:

terminate in class VarPAggregator<V extends Number>