Showing posts with label function. Show all posts
Showing posts with label function. Show all posts

Monday, June 15, 2009

SQL FUNCTION ExtractNumbers

SQL FUNCTION ExtractNumbers

Create Function ExtractNumbers
(
@str_passed varchar(max)
)

Returns varchar(50)

AS

BEGIN
    declare @val varchar(50), @i int
    select @val = '', @i = 1

    while (@i <= len(@ str_passed))
        select @val= @val+ (CASE when substring(@ str_passed,@i,1) like '[0-9]' 
                                  then substring(@ str_passed,@i,1) else '' END),
              SET @i = @i + 1

    Return @val
END

Usage:-

SELECT SrNo,  dbo. ExtractNumbers(AlphaNumCol) as NumColData from TableName

Drop commas from '45,22,135'
or Drop dash & braces from '(91)123-456-789'
or Drop alphabets from 'C99B33A1234'

Monday, February 9, 2009

Scalar User Defined Functions and Computed Columns

Scalar User Defined Functions and Computed Columns

Came across an interesting SQL problem where a customer has a table with a primary key and X numerical fields. For each record the maximum value in these X fields was needed.

The issue was how to accomplish this efficiently? Or more accurately the least inefficient way of doing it is.
One option suggested was to have to UNION the table with itself X times and then do a MAX aggregation since there was a lot of data.

The more interesting option, which it turns out not many people are aware of, is to use a Scalar User Defined Function (UDF) to calculate the maximum value.

Here's an example of this in action:

CREATE FUNCTION CubicVolume
-- Input dimensions in centimeters
(@CubeLength decimal(4,1), @CubeWidth decimal(4,1),
@CubeHeight decimal(4,1) )
RETURNS decimal(12,3) -- Cubic Centimeters.
AS
BEGIN
RETURN ( @CubeLength * @CubeWidth * @CubeHeight )
END
CREATE TABLE Bricks
(
BrickPartNmbr int PRIMARY KEY,
BrickColor nchar(20),
BrickHeight decimal(4,1),
BrickLength decimal(4,1),
BrickWidth decimal(4,1),
BrickVolume AS
(
dbo.CubicVolume(BrickHeight,
BrickLength, BrickWidth)
)
)

Basically the scalar UDF is called for each row returned from a SELECT. The column itself is not actually stored in the SQL Server table. Any INSERT and UPDATE on the table do not calculate the value for the computed column. Now obviously this is an overhead that may not be acceptable if the table is very static and read a lot. Here, it may be more efficient to perform the calculation once on INSERT or UPDATE of the table with INSTEAD OF triggers or another similar method.

Wednesday, February 4, 2009

Javascript - Compare two Dates

Javascript - Compare two Dates

function CompareDates() {
var txtEffDt = document.getElementById("txtEffectiveDt").value.split("/");
var txtExpDt = document.getElementById("txtExpiryDt").value.split("/");
var date1 = new Date(txtEffDt[2]+'/'+txtEffDt[0]+'/'+txtEffDt[1]);
var date2 = new Date(txtExpDt[2]+'/'+txtExpDt[0]+'/'+txtExpDt[1]);

if (date1 > date2) {
alert("Expiry Date cannot be less than Effective Date");
return false;
}
}

Tuesday, February 3, 2009

Convert an Integer/Number into words

SET NOCOUNT ON
=============================================
Description: Converts an integer into words,
viz., --
master.dbo.fnSpellInteger(10129) ==> "Ten Thousand One Hundred Twenty-Nine"
=============================================
USE MASTER
IF OBJECT_ID('dbo.fnSpellInteger') IS NOT NULL DROP FUNCTION fnSpellIntegerGO
CREATE FUNCTION dbo.fnSpellInteger ( @number int )RETURNS VARCHAR(100)ASBEGIN -- For debugging outside of the UDF: DECLARE @debug bit SET @debug = 0
DECLARE @result VARCHAR(100), @word VARCHAR(100), @group VARCHAR(100) DECLARE @i int, @j int, @m int, @digit VARCHAR(2), @cn VARCHAR(20)
IF @number = 0 RETURN 'Zero'
SELECT @result = '', @word = '', @group = '' SET @cn = @number SET @cn = REPLACE(@cn,',','') SET @m = LEN(@cn) % 3 IF @m > 0 SET @cn = REPLICATE('0',3-@m) + @cn -- Left pad with zeroes to a multiple of 3
SET @i = 1 SET @j = LEN(@cn)-@i+1 SET @m = @i % 3 WHILE @i <= LEN(@cn) BEGIN -- @i is 1 origin index into numeric string while @m = @i modulo 3 -- If the middle digit of each group of 3 is a '1' then this is a 'Ten' or a '...teen' IF @m = 2 AND SUBSTRING(@cn,@i,1) = '1' BEGIN SET @digit = SUBSTRING(@cn,@i,2) -- Skip rightmost digit of 3 if processing teens SET @i = @i + 1 END ELSE SET @digit = SUBSTRING(@cn,@i,1)
SET @word = CASE WHEN @m = 0 THEN -- Rightmost digit of group of 3 CASE @digit WHEN '0' THEN '' WHEN '1' THEN 'One' WHEN '2' THEN 'Two' WHEN '3' THEN 'Three' WHEN '4' THEN 'Four' WHEN '5' THEN 'Five' WHEN '6' THEN 'Six' WHEN '7' THEN 'Seven' WHEN '8' THEN 'Eight' WHEN '9' THEN 'Nine' END + CASE WHEN (@group <> '' OR @digit <> '0') AND (@j+2) / 3 = 2 THEN ' Thousand' WHEN (@group <> '' OR @digit <> '0') AND (@j+2) / 3 = 3 THEN ' Million' WHEN (@group <> '' OR @digit <> '0') AND (@j+2) / 3 = 4 THEN ' Billion' ELSE '' END WHEN LEN(@digit) = 2 THEN -- Special case when middle digit is a '1' CASE @digit WHEN '10' THEN 'Ten' WHEN '11' THEN 'Eleven' WHEN '12' THEN 'Twelve' WHEN '13' THEN 'Thirteen' WHEN '14' THEN 'Fourteen' WHEN '15' THEN 'Fifteen' WHEN '16' THEN 'Sixteen' WHEN '17' THEN 'Seventeen' WHEN '18' THEN 'Eighteen' WHEN '19' THEN 'Nineteen' END + CASE WHEN (@group <> '' OR @digit <> '00') AND (@j+2) / 3 = 2 THEN ' Thousand' WHEN (@group <> '' OR @digit <> '00') AND (@j+2) / 3 = 3 THEN ' Million' WHEN (@group <> '' OR @digit <> '00') AND (@j+2) / 3 = 4 THEN ' Billion' ELSE '' END WHEN @m = 2 THEN -- Middle digit of group of 3 CASE @digit WHEN '2' THEN 'Twenty' WHEN '3' THEN 'Thirty' WHEN '4' THEN 'Forty' WHEN '5' THEN 'Fifty' WHEN '6' THEN 'Sixty' WHEN '7' THEN 'Seventy' WHEN '8' THEN 'Eighty' WHEN '9' THEN 'Ninety' ELSE '' END WHEN @m = 1 THEN -- Leftmost digit of group of 3 CASE @digit WHEN '0' THEN '' WHEN '1' THEN 'One' WHEN '2' THEN 'Two' WHEN '3' THEN 'Three' WHEN '4' THEN 'Four' WHEN '5' THEN 'Five' WHEN '6' THEN 'Six' WHEN '7' THEN 'Seven' WHEN '8' THEN 'Eight' WHEN '9' THEN 'Nine' END + CASE WHEN @digit <> '0' THEN ' Hundred' ELSE '' END END
SET @group = @group + RTRIM(@word) -- Group value
IF @word <> '' BEGIN DECLARE @prefix VARCHAR(20) IF CHARINDEX(' ',@word) > 0 SET @prefix = LEFT(@word,CHARINDEX(' ',@word)) ELSE SET @prefix = @word IF RIGHT(@result,2) = 'ty' AND @prefix IN ('One','Two','Three','Four','Five','Six','Seven','Eight','Nine') SET @result = @result + '-' + LTRIM(@word) ELSE SET @result = @result + ' ' + LTRIM(@word) END -- The following needs to be outside of a UDF to work: --IF @debug = 1 SELECT @cn as 'Number', @i as '@i', @j as '@j', @m as '@m', @digit as '@digit', CAST(replace(@group,' ','`') AS CHAR(30)) as '@group', @word as '@word', @result as '@result' SET @i = @i + 1 SET @j = LEN(@cn)-@i+1 SET @m = @i % 3 IF @m = 1 SET @group = '' -- Clear group value when starting a new one
END
IF @result = '' SET @result = '0' RETURN LTRIM(@Result)
ENDGO
SET NOCOUNT ON

Description: Converts a string numeric expression into words,
viz., --
master.dbo.fnSpellNumber('15.99') ==> "Fifteen and Ninety-Nine Hundredths"-- Notes: Uses fnSpellInteger to convert an integer into words-- Example: fnSpellNumber can be used to generate pseudo-random test character data/* set nocount on declare @rand int, @i int set @rand = rand(131)*100 set @i = 0
while @i < 5 begin set @i = @i + 1 select 'insert(id,number,words) values(' + cast(@i as varchar(5)) + ',' + cast(@rand as varchar(5)) + ',''' + master.dbo.fnspellnumber(@rand) + ''')' set @rand = rand()*100 end*/-- =============================================
USE MASTER
IF OBJECT_ID('master.dbo.fnSpellNumber') IS NOT NULL DROP FUNCTION fnSpellNumberGO
CREATE FUNCTION dbo.fnSpellNumber ( @number varchar(20) )RETURNS VARCHAR(200)AS--For debugging: declare @number varchar(20) set @number = '192.1'BEGIN -- This is for use outside of a function: DECLARE @debug bit SET @debug = 0
DECLARE @result varchar(200), @word varchar(100) DECLARE @i int, @intpart varchar(20), @decpart varchar(20) SET @word = LTRIM(RTRIM(@number)) -- Check for a bad number, e.g., one with embedded spaces IF ISNUMERIC(@word) = 0 RETURN '<<>>'
SET @i = CHARINDEX('.', @word) -- Remove trailing zeroes for any decimal portion IF @i > 0 -- Number contains a decimal point BEGIN WHILE RIGHT(@word,1) = '0' SET @word = LEFT(@word,LEN(@word)-1) IF @word = '' SET @word = '0' END -- Insert a decimal point at the end if none was specified IF @i = 0 -- No decimal point BEGIN SET @word = @number + '.' SET @i = CHARINDEX('.', @word) END
SET @intpart = LEFT(@word,@i-1) -- Extract the integer part of the number if any IF LEN(@intpart) > 0 SET @result = master.dbo.fnSpellInteger(CAST(@intpart AS int)) ELSE SET @result = ''
-- Extract the decimal portion of the number SET @decpart = RIGHT(@word,LEN(@word)-@i) -- @i is position of decimal point
IF LEN(@decpart) > 0 BEGIN IF @result = 'Zero' SET @result = '' ELSE IF @result <> '' SET @result = @result + ' and '
SET @result = @result + master.dbo.fnSpellInteger(@decpart) + CASE LEN(@decpart) WHEN 0 THEN '' WHEN 1 THEN ' Tenths' WHEN 2 THEN ' Hundredths' WHEN 3 THEN ' One-Thousandths' WHEN 4 THEN ' Ten-Thousandths' WHEN 5 THEN ' One-Hundred-Thousandths' WHEN 6 THEN ' One-Millionths' WHEN 7 THEN ' Ten-Millionths' WHEN 8 THEN ' One-Hundred-Millionths' WHEN 9 THEN ' One-Billionths' END -- Check for a valid plural IF @decpart = 1 SET @result = LEFT(@result, LEN(@result)-1) -- Remove last "s" for just 1 END -- This is for use outside of a function: if @debug = 1 select @word as '@word', @i as '@i', @intpart as '@intpart', @decpart as '@decpart', @result as '@result' RETURN @result
ENDGO