PERMUTATIONA

Updated: 30 May 2017

Use the SQL Server scalar function PERMUTATIONA to calculate the number of permutations with replacement defined as:

Syntax

SELECT [wct].[PERMUTATIONA] (

<@n, int,>

,<@k, int,>)

Arguments

Input Name | Definition |

@n | Number of items |

@k | Number chosen |

Return Type

float

Remarks

- If
**@n**< 0 and**@k**< 0 then NULL is returned. - If
**@k**< 0 then NULL is returned. - Available in XLeratorDB / statistics 2008 only

Examples

Example #1

SELECT wct.PERMUTATIONA(10,3) as PERMUTATIONA

This produces the following result.

Example #2

Calculate the probability of 2 people having the same birthday in a room containing n people.

SELECT

x.n

,1 - wct.PERMUT(365,x.n)/wct.PERMUTATIONA(365,x.n) as [p(n)]

FROM (VALUES

(10),(20),(22),(23),(30),(57))x(n)

This produces the following result.

See Also