A Few Mathematical UDFs

,


Introduction

I would like to write the series of articles about useful User-Defined

Functions grouped by the following categories:

  • Date and Time User-Defined Functions
  • Mathematical User-Defined Functions
  • Metadata User-Defined Functions
  • Security User-Defined Functions
  • String User-Defined Functions
  • System User-Defined Functions
  • Text and Image User-Defined Functions

In this article, I wrote some useful Mathematical User-Defined

Functions.

Mathematical UDFs

These scalar User-Defined Functions perform a calculation, usually

based on input values provided as arguments, and return a numeric

value.

To download Mathematical User-Defined Functions click this link:

Download Mathematical UDFs

Factorial

Returns the factorial value of the given number.

Syntax
Factorial ( number )
Arguments
number - Is the integer value.
Return Types
bigint

The function's text:

CREATE FUNCTION Factorial

( @number int )

RETURNS bigint

AS

BEGIN

DECLARE @i int, @factorial bigint

IF @number > 20 RETURN 0

SET @i = 1

SET @factorial = 1

WHILE @i <= @number

BEGIN

SET @factorial = @factorial * @i

SET @i = @i + 1

END

RETURN @factorial

END

GO

Examples

This example returns the factorial value of the number 5:

SELECT dbo.Factorial(5)

GO

Here is the result set:

--------------------
120
(1 row(s) affected)

PercentFrom

Returns the percent of the expression1 in the expression2.

Syntax
PercentFrom ( expression1, expression2 )
Arguments
expression1 - Is an expression of the exact numeric or approximate numeric

data type category.

expression2 - Is an expression of the exact numeric or approximate numeric

data type category.

Return Types
float

The function's text:

CREATE FUNCTION PercentFrom

( @expression1 SQL_VARIANT,

@expression2 SQL_VARIANT )

RETURNS float

AS

BEGIN

RETURN (CAST(@expression1 AS FLOAT)/CAST(@expression2 AS FLOAT)*100)

END

GO

Examples

This example returns the percent of the 137 in the 273:

SELECT dbo.PercentFrom(137, 273)

GO

Here is the result set:

-----------------------------------------------------
50.183150183150182
(1 row(s) affected)

PercentValue

Returns the percent's value from the given expression for the

given percent.

Syntax
PercentValue ( expression, percent )
Arguments
expression - Is an expression of the exact numeric or approximate numeric

data type category.

percent - Is the integer value.

Return Types
float

The function's text:

CREATE FUNCTION PercentValue

( @expression SQL_VARIANT,

@percent int )

RETURNS float

AS

BEGIN

RETURN ( CAST(@expression AS FLOAT) / 100 * @percent )

END

GO

Examples

Returns the percent's value from the number 137 for the percent 11:

SELECT dbo.PercentValue (137, 11)

GO

Here is the result set:

-----------------------------------------------------
15.07
(1 row(s) affected)

Degree

Returns the degree for the given number and degree value.

Syntax
Degree ( number, degree )
Arguments
number - Is an expression of the exact numeric or approximate numeric

data type category.

degree - Is the integer value.

Return Types
float

The function's text:

CREATE FUNCTION Degree

( @number SQL_VARIANT,

@degree int )

RETURNS float

AS

BEGIN

DECLARE @i int, @res float

SET @i = 1

SET @res = 1

WHILE @i <= @degree

BEGIN

SET @res = CAST(@number AS FLOAT) * @res

SET @i = @i + 1

END

RETURN @res

END

GO

Examples

Returns the degree 4 for the number 3:

SELECT dbo.Degree(3, 4)

GO

Here is the result set:

-----------------------------------------------------
81.0
(1 row(s) affected)

Allocation

Returns the allocation from the m by n.

Syntax
Allocation ( m, n )
Arguments
m - Is the integer value.

n - Is the integer value.

Return Types
int

The function's text:

CREATE FUNCTION Allocation

( @m int,

@n int )

RETURNS int

AS

BEGIN

RETURN (dbo.Factorial(@m)/dbo.Factorial(@m-@n))

END

GO

Examples

Returns the allocation from the 5 by 3:

SELECT dbo.Allocation(5,3)

GO

Here is the result set:

-----------
60
(1 row(s) affected)

Combination

Returns the combination from the m by n.

Syntax
Combination ( m, n )
Arguments
m - Is the integer value.

n - Is the integer value.

Return Types
int

The function's text:

CREATE FUNCTION Combination

( @m int,

@n int )

RETURNS int

AS

BEGIN

RETURN (dbo.Factorial(@m)/(dbo.Factorial(@m-@n)*dbo.Factorial(@n)))

END

GO

Examples

Returns the combination from the 5 by 3:

SELECT dbo.Combination(5,3)

GO

Here is the result set:

-----------
10
(1 row(s) affected)

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