Real Unique Random AlphaNumeric

Question

Hi,

In SQL, how can I create a real random 256 alpha-numeric string without having to kill my server with looping and looping?

Thanks,
Jassim

Answer 1

This gives you a 344 character long Base64 string. It is not entirely alphanumeric, but it is random.

DECLARE @x varchar(4000)
SELECT @x = (SELECT crypt_gen_random(256) AS x
             FOR XML PATH('root'), TYPE).value('/root[1]/x[1]', 'varchar(4000)')
SELECT len(@x), @x

Answer 2

Try
SELECT
REPLACE(CAST(NEWID() AS VARCHAR(256)),'-','') + REPLACE(CAST(NEWID() AS VARCHAR(256)),'-','') + REPLACE(CAST(NEWID() AS VARCHAR(256)),'-','')
+REPLACE(CAST(NEWID() AS VARCHAR(256)),'-','')
+REPLACE(CAST(NEWID() AS VARCHAR(256)),'-','') + REPLACE(CAST(NEWID() AS VARCHAR(256)),'-','') + REPLACE(CAST(NEWID() AS VARCHAR(256)),'-','')
+REPLACE(CAST(NEWID() AS VARCHAR(256)),'-','') AS b

Answer 3

Hi @Jassim Al Rahma
I usually use NEWID() to get unique string,like this:

SELECT NEWID();  
  
SELECT REPLACE(CONVERT(VARCHAR(64),NEWID()),'-','');--Remove '-'  

In this way, you can get a random string with a length of 32. Since your request is for a length of 256, you need to connect 8 strings together.
If you don't mind the presence of characters other than AlphaNumeric in the string, then you can refer to Erland's answer.

Best regards,
LiHong