org.apache.flink.table.runtime.operators.rank

Enum RankType

java.lang.Object

java.lang.Enum<RankType>

org.apache.flink.table.runtime.operators.rank.RankType

All Implemented Interfaces:

Serializable, Comparable<RankType>

public enum RankType
extends Enum<RankType>

An enumeration of rank type, usable to show how exactly generate rank number.

Enum Constant Summary

Enum Constants

Enum Constant and Description
DENSE_RANK is similar to the RANK by generating a unique rank number for each distinct row within the partition based on the order, starting at 1 for the first row in each partition, ranking the rows with equal values with the same rank number, except that it does not skip any rank, leaving no gaps between the ranks.
RANK Returns a unique rank number for each distinct row within the partition based on the order, starting at 1 for the first row in each partition, with the same rank for duplicate values and leaving gaps between the ranks; this gap appears in the sequence after the duplicate values.
ROW_NUMBER Returns a unique sequential number for each row within the partition based on the order, starting at 1 for the first row in each partition and without repeating or skipping numbers in the ranking result of each partition.

Method Summary

Modifier and Type	Method and Description
static RankType	valueOf(String name) Returns the enum constant of this type with the specified name.
static RankType[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

ROW_NUMBER

public static final RankType ROW_NUMBER

Returns a unique sequential number for each row within the partition based on the order, starting at 1 for the first row in each partition and without repeating or skipping numbers in the ranking result of each partition. If there are duplicate values within the row set, the ranking numbers will be assigned arbitrarily.

RANK

public static final RankType RANK

Returns a unique rank number for each distinct row within the partition based on the order, starting at 1 for the first row in each partition, with the same rank for duplicate values and leaving gaps between the ranks; this gap appears in the sequence after the duplicate values.

DENSE_RANK

public static final RankType DENSE_RANK

is similar to the RANK by generating a unique rank number for each distinct row within the partition based on the order, starting at 1 for the first row in each partition, ranking the rows with equal values with the same rank number, except that it does not skip any rank, leaving no gaps between the ranks.

Method Detail

values

public static RankType[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (RankType c : RankType.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static RankType valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null