How do I generate random number for each row in a TSQL Select?

Question

I need a different random number for each row in my table. The following seemingly obvious code uses the same random value for each row.

SELECT table_name,          


        

Answer 1

Random number generation between 1000 and 9999 inclusive:

FLOOR(RAND(CHECKSUM(NEWID()))*(9999-1000+1)+1000)

"+1" - to include upper bound values(9999 for previous example)

Answer 2

It's as easy as:

DECLARE @rv FLOAT;
SELECT @rv = rand();

And this will put a random number between 0-99 into a table:

CREATE TABLE R
(
    Number int
)

DECLARE @rv FLOAT;
SELECT @rv = rand();

INSERT INTO dbo.R
(Number)
    values((@rv * 100));

SELECT * FROM R

Answer 3

select round(rand(checksum(newid()))*(10)+20,2)

Here the random number will come in between 20 and 30. round will give two decimal place maximum.

If you want negative numbers you can do it with

select round(rand(checksum(newid()))*(10)-60,2)

Then the min value will be -60 and max will be -50.

Answer 4

select ABS(CAST(CAST(NEWID() AS VARBINARY) AS INT)) as [Randomizer]

has always worked for me

Answer 5

You would need to call RAND() for each row. Here is a good example

https://web.archive.org/web/20090216200320/http://dotnet.org.za/calmyourself/archive/2007/04/13/sql-rand-trap-same-value-per-row.aspx

Answer 6

Answering the old question, but this answer has not been provided previously, and hopefully this will be useful for someone finding this results through a search engine.

With SQL Server 2008, a new function has been introduced, CRYPT_GEN_RANDOM(8), which uses CryptoAPI to produce a cryptographically strong random number, returned as VARBINARY(8000). Here's the documentation page: https://docs.microsoft.com/en-us/sql/t-sql/functions/crypt-gen-random-transact-sql

So to get a random number, you can simply call the function and cast it to the necessary type:

select CAST(CRYPT_GEN_RANDOM(8) AS bigint)

or to get a float between -1 and +1, you could do something like this:

select CAST(CRYPT_GEN_RANDOM(8) AS bigint) % 1000000000 / 1000000000.0