Generate unique random numbers using SQL

Question

I have some SQL code which generates random numbers using the following technique:

DECLARE @Random1 INT, @Random2 INT, @Random3 INT, @Random4 INT, @Random5 I         


        

Answer 1

For Laravel:

 public function generatUniqueId()
    {
        $rand = rand(10000, 99999);
        $itemId = $rand;
        while (true) {
            if (!BookItem::whereBookItemId($itemId)->exists()) {
                break;
            }
            $itemId = rand(10000, 99999);
        }

        return $itemId;
    }

Answer 2

I guess you could do something like this much simpler and much easier

DECLARE @Upper INT;
DECLARE @Lower INT;
SET @Lower = 1;     /* -- The lowest random number */
SET @Upper = 49;    /* -- The highest random number */
    
    
SELECT @Lower + CONVERT(INT, (@Upper-@Lower+1)*RAND());

For getting a random number without repetition, this will do the job

WITH CTE 
AS
(
    SELECT  randomNumber, COUNT(1) countOfRandomNumber
    FROM (
    SELECT ABS(CAST(NEWID() AS binary(6)) %49) + 1 randomNumber
    FROM sysobjects
    ) sample
    GROUP BY randomNumber
)
SELECT TOP 5 randomNumber
FROM CTE
ORDER BY newid() 

To set the highest limit, you can replace 49 with your highest limit number.

Answer 3

You can use Rand() function .

select CEILING(RAND() *<max of random numbers))