XLeratorDB/statistics Documentation
Updated: 30 May 2017
Use the SQL Server scalar function LPERMUT to calculate the natural logarithm of the PERMUT function. The PERMUT function calculates the number of permutations without replacement defined as:
Syntax
SELECT [wct].[LPERMUT] (
<@n, int,>
,<@k, int,>)
Arguments
| Input Name | Definition |
| @n | Number of items |
| @k | Number chosen |
Return Type
Remarks
- If @n < 0 then NULL is returned.
- If @k < 0 then NULL is returned.
- If @k > n then NULL is returned.
- Available in XLeratorDB / statistics 2008 only
Examples
Example #1
SELECT wct.LPERMUT(10,3) as LPERMUT
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 - EXP(wct.LPERMUT(365,x.n)-wct.LPERMUTA(365,x.n)) as [p(n)]
FROM (VALUES
(10),(20),(22),(23),(30),(57))x(n)
This produces the following result.
See Also