CODEWITHSUNDEEP
t-sql
Lisa
Lisa

Reputation: 3181

How can I generate random strings in TSQL

How can I generate a random string? I wrote the following, which gave my only one letter as a result !

declare @alphaCount int
set @alphaCount =  @alphaCount +1
CHAR(@alphaCount)

Thanks in advance!

Upvotes: 2

Views: 1695

Answers (4)

Martin Smith
Martin Smith

Reputation: 452978

This will give you 10,000 rows in the specified format.

DECLARE @Numbers  TABLE
(
n INT PRIMARY KEY
);


WITH E00(N) AS (SELECT 1 UNION ALL SELECT 1),   --2
        E02(N) AS (SELECT 1 FROM E00 a, E00 b), --4
        E04(N) AS (SELECT 1 FROM E02 a, E02 b), --16
        E08(N) AS (SELECT 1 FROM E04 a, E04 b), --256
        E16(N) AS (SELECT 1 FROM E08 a, E08 b)  --65,536
INSERT INTO @Numbers
SELECT TOP 10000 ROW_NUMBER() OVER (ORDER BY (SELECT 0))
FROM E16        

SELECT CAST((SELECT TOP 20 CHAR(CASE
                                  WHEN Abs(Checksum(Newid()))%2 = 0 THEN 65
                                  ELSE 97
                                END + Abs(Checksum(Newid()))%26)
             FROM   @Numbers n1
             WHERE  n1.n >= -n2.n /*So it gets re-evaluated for each row!*/
             FOR XML PATH('')) AS CHAR(20))
FROM   @Numbers n2

Upvotes: 6

brad.v
brad.v

Reputation: 327

This should do the trick for how to

DECLARE @length         Integer
DECLARE @return         VarChar(1000)
DECLARE @index          Integer
DECLARE @value          Integer

SET @length = 12
SET @return = '';

IF @length > 1000
    SET @length = 1000;

IF @length <= 0
    SELECT @return;

SET @index = 0;

WHILE @index < @length
BEGIN
    SET @value = (64 * RAND()) + 32;
    SET @return = @return + CHAR(@value);

    SET @index = @index + 1;
END 

SELECT @return;

If you wanted to make this a user defined function, i liked the option 'steve' had in this article. here

Upvotes: 0

Mark SQLDev
Mark SQLDev

Reputation: 539

This procedure will work. You may have to create a function with it, but it has the right ideas.

Upvotes: 1

Mark Ransom
Mark Ransom

Reputation: 308111

Fill a temporary table with a list of random words. Then use CROSS JOIN to combine every word with every other word, to get a whole ton of data with little effort.

select l.word+' '+r.word from #Words as l
cross join #Words as r

Upvotes: 1

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