Example
SubString(‘0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ’, dbo.Rnd(1,36), 1)

For a random digit or letter and that list could obviously be extended to include any characters you wish.

Part 1 – The randomizer view, this is nothing new, just generating a random float in a view so it can be used in a function.
CREATE VIEW [dbo].[Randomizer] AS
SELECT abs((convert(bigint,convert(binary(8),newid()))*0.000000000000001)%1.0) AS n

Part 2 – A Random function that takes min and max parameters so that we can generate a random value within desired bounds.

CREATE FUNCTION dbo.Rnd( @min bigint, @max bigint ) RETURNS bigint AS
BEGIN

RETURN convert(bigint,
(@max – @min + 1)
*
(SELECT TOP 1 n FROM dbo.Randomizer)
+
@min
);
END

Part 3 – A generic mask substitution function so that we can ask specify any mask we want. I will only implement the very most basic set of substitutions. You can extend these in simple ways.
CREATE FUNCTION dbo.RandomText( @mask varchar(64) ) RETURNS varchar(64) AS
BEGIN
– Goal: Substatute mask tokens with random values
– Inputs: @mask – a string with subtatution tokens and literals
– Tokens: # – will be replaced with a random digit [0-9]
– A – will be replaced with a random upper case english letter [A-Z]

SELECT
@mask = Stuff( @mask, start, 1, replacement )
FROM (
SELECT
n AS start,
CASE SubString( @mask, n, 1 )
WHEN ‘#’ THEN char( dbo.Rnd(48,57) ) — [0-9]
WHEN ‘A’ THEN char( dbo.Rnd(65,90) ) — [A-Z]
END AS replacement
FROM (
SELECT (1+n1.n+n10.n) AS n
FROM
(SELECT 0 AS n UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) n1
CROSS JOIN (SELECT 0 AS n UNION SELECT 10 UNION SELECT 20 UNION SELECT 30 UNION SELECT 40 UNION SELECT 50 UNION SELECT 60) AS n10
WHERE
(1+n1.n+n10.n) BETWEEN 1 AND Len(@mask)
) sequence
WHERE
SubString( @mask, n, 1 ) IN (‘#’,'A’)
) substatutions

RETURN @mask

END

Very new to SQL, T-SQL – so be kind. :-)

Use RAND() to get a number between 1 and 9, and use the number as an index into your number string.

If the number is given as a long string with varying lengths, you may need to expand the list first. There is a good article on how to do that here: http://bradsruminations.blogspot.com/2009/10/un-making-list-or-shredding-of-evidence.html

I think the first script, is flawed.
This one:
—- Create the variables for the random number generation
DECLARE @Random INT;
DECLARE @Upper INT;
DECLARE @Lower INT

—- This will create a random number between 1 and 999
SET @Lower = 1 —- The lowest random number
SET @Upper = 999 —- The highest random number
SELECT @Random = ROUND(((@Upper – @Lower -1) * RAND() + @Lower), 0)
SELECT @Random

If you set a lower limit of 1, and upper limit 2, it will always return one.

If you remove the ‘-1′ from here: ROUND(((@Upper – @Lower -1) * RAND() + @Lower), 0) it returns 1 and 2.

Maybe I am mistaken and this is a particular case.

Thanks for the great site, I found many useful scripts here. :)

Regards,
Alex Luca

I have table with 100 records, how can I update a field on this with random numbers from 1 thru 100, when I do this using RANd() I do get duplicate random numers in the file which does not help me. Any help?

Love the blog.

DECLARE @Random_Sales INT;
DECLARE @Upper_Sales INT;
DECLARE @Lower_Sales INT;
DECLARE @Random_Profit INT;
DECLARE @Upper_Profit INT;
DECLARE @Lower_Profit INT;
DECLARE @Random_Percent INT;
DECLARE @Upper_Percent INT;
DECLARE @Lower_Percent INT

SET @Lower_Sales = 500000
SET @Upper_Sales = 599999
SET @Lower_Profit = 60000
SET @Upper_Profit = 99999
SET @Lower_Percent = 15
SET @Upper_Percent = 20

SELECT @Random_Sales = ROUND(((@Upper_Sales - @Lower_Sales -1) * RAND() + @Lower_Sales), 0)
SELECT @Random_Sales
SELECT @Random_Sales = ROUND(((@Upper_Sales - @Lower_Sales -1) * RAND() + @Lower_Sales), 0)
SELECT @Random_Sales
SELECT @Random_Profit = ROUND(((@Upper_Profit - @Lower_Profit -1) * RAND() + @Lower_Profit), 0)
SELECT @Random_Profit
SELECT @Random_Percent = ROUND(((@Upper_Percent - @Lower_Percent -1) * RAND() + @Lower_Percent), 0)
SELECT @Random_Percent

You are the best.

SELECT ABS(CAST(NEWID() AS binary(6)) %3)

I will always get either a 0, 1, or 2 – perfect!

However, what I am ultimately trying to do is to assign a mapped value to a field depending on the value of the random number generated above, like this:

UPDATE MyTable
SET MyField =
CASE ABS(CAST(NEWID() AS binary(6)) % 3)
WHEN 0 THEN ‘red’
WHEN 1 THEN ‘blue’
WHEN 2 THEN ‘green’
END
WHERE KeyField = ’somevalue’

Apparently the CASE statement is getting confused at times, and although in most cases, the field will be be updated with ‘red,’ ‘blue,’ or ‘green,’ at least 30% of the time, the CASE statement returns NULL! I don’t know why this would possibly be happening, since using ABS(CAST(NEWID() AS binary(6)) % 3) without a CASE statement NEVER returns NULL!

To test this yourself, first trying executing this several times:

SELECT ABS(CAST(NEWID() AS binary(6)) % 3)

You’ll see that you never get a NULL returned.

Next, try executing this several times:

SELECT CASE ABS(CAST(NEWID() AS binary(6)) % 3)
WHEN 0 THEN ‘zero’
WHEN 1 THEN ‘one’
WHEN 2 THEN ‘two’
END

You’ll many times that you get a NULL returned.

HELP!

LIMIT is not ANSI SQL. Not Especially T-SQL . LIMIT Key word is only in MYSQL.

~ IM.

I tried using select stmt (below) but I had message error on LIMIT function.

Select stmt:
select * from table_name order by RAND() limit 5

error msg:
Msg 102, Level 15, State 1, Line 1
Incorrect syntax near ‘limit’.

CREATE PROCEDURE GetRandomInteger
(
@Min int,
@Max int,
@rv int OUTPUT
)
AS
BEGIN
DECLARE @Rand float

SELECT @Rand = ((@Max – @Min + 1) * RAND(CONVERT(int, CONVERT(varbinary, NEWID())))) + .5 + (@Min – 1)

SELECT @rv = ROUND(@Rand, 0)

END

for example, say the query selects 12 different rows, how can I then rendomly select one of the twelve and drop the other 11?

thankyou

Matt