生成与T-SQL的随机字符串(Generating random strings with T-SQ

如果你想生成使用T-SQL一个伪随机字母数字字符串，你会怎么做呢？ 你会如何排除像美元符号，破折号字符，并从中斜线？

Answer 1:

当生成随机数据，特别是用于测试，它使数据随机的，但重复性非常有用的。 秘诀就是使用显式的种子随机函数，以便当试验是用相同的种子再次运行时，它产生再次一模一样的字符串。 下面是可重复的方式产生目标名称的功能的简化示例：

alter procedure usp_generateIdentifier
    @minLen int = 1
    , @maxLen int = 256
    , @seed int output
    , @string varchar(8000) output
as
begin
    set nocount on;
    declare @length int;
    declare @alpha varchar(8000)
        , @digit varchar(8000)
        , @specials varchar(8000)
        , @first varchar(8000)
    declare @step bigint = rand(@seed) * 2147483647;

    select @alpha = 'qwertyuiopasdfghjklzxcvbnm'
        , @digit = '1234567890'
        , @specials = '_@# '
    select @first = @alpha + '_@';

    set  @seed = (rand((@seed+@step)%2147483647)*2147483647);

    select @length = @minLen + rand(@seed) * (@maxLen-@minLen)
        , @seed = (rand((@seed+@step)%2147483647)*2147483647);

    declare @dice int;
    select @dice = rand(@seed) * len(@first),
        @seed = (rand((@seed+@step)%2147483647)*2147483647);
    select @string = substring(@first, @dice, 1);

    while 0 < @length 
    begin
        select @dice = rand(@seed) * 100
            , @seed = (rand((@seed+@step)%2147483647)*2147483647);
        if (@dice < 10) -- 10% special chars
        begin
            select @dice = rand(@seed) * len(@specials)+1
                , @seed = (rand((@seed+@step)%2147483647)*2147483647);
            select @string = @string + substring(@specials, @dice, 1);
        end
        else if (@dice < 10+10) -- 10% digits
        begin
            select @dice = rand(@seed) * len(@digit)+1
                , @seed = (rand((@seed+@step)%2147483647)*2147483647);
            select @string = @string + substring(@digit, @dice, 1);
        end
        else -- rest 80% alpha
        begin
            declare @preseed int = @seed;
            select @dice = rand(@seed) * len(@alpha)+1
                , @seed = (rand((@seed+@step)%2147483647)*2147483647);

            select @string = @string + substring(@alpha, @dice, 1);
        end

        select @length = @length - 1;   
    end
end
go

当运行测试呼叫者产生它与试运行（将其保存在结果表中），然后沿着晶种，与此类似传递相关联的随机种子：

declare @seed int;
declare @string varchar(256);

select @seed = 1234; -- saved start seed

exec usp_generateIdentifier 
    @seed = @seed output
    , @string = @string output;
print @string;  
exec usp_generateIdentifier 
    @seed = @seed output
    , @string = @string output;
print @string;  
exec usp_generateIdentifier 
    @seed = @seed output
    , @string = @string output;
print @string;  

更新2016年2月17日：查看评论波纹管，原来的程序有它先进的随机种子的方式的问题。 我更新的代码，并且还固定提到的off-by-一个问题。

Answer 2:

使用GUID

SELECT @randomString = CONVERT(varchar(255), NEWID())

很短 ...

Answer 3:

类似于第一个例子，但更多的灵活性：

-- min_length = 8, max_length = 12
SET @Length = RAND() * 5 + 8
-- SET @Length = RAND() * (max_length - min_length + 1) + min_length

-- define allowable character explicitly - easy to read this way an easy to 
-- omit easily confused chars like l (ell) and 1 (one) or 0 (zero) and O (oh)
SET @CharPool = 
    'abcdefghijkmnopqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ23456789.,-_!$@#%^&*'
SET @PoolLength = Len(@CharPool)

SET @LoopCount = 0
SET @RandomString = ''

WHILE (@LoopCount < @Length) BEGIN
    SELECT @RandomString = @RandomString + 
        SUBSTRING(@Charpool, CONVERT(int, RAND() * @PoolLength), 1)
    SELECT @LoopCount = @LoopCount + 1
END

我忘了提及的其他功能，使这更为灵活。 通过在@CharPool重复字符的块，则可以提高对某些字符的加权，使得它们更容易被选择。

Answer 4:

使用下面的代码返回一个简短的字符串：

SELECT SUBSTRING(CONVERT(varchar(40), NEWID()),0,9)

Answer 5:

如果您正在运行SQL Server 2008或更高版本，可以使用新的加密功能crypt_gen_random（），然后使用base64编码，从而使它成为一个字符串。 这将为多达8000个字符的工作。

declare @BinaryData varbinary(max)
    , @CharacterData varchar(max)
    , @Length int = 2048

set @BinaryData=crypt_gen_random (@Length) 

set @CharacterData=cast('' as xml).value('xs:base64Binary(sql:variable("@BinaryData"))', 'varchar(max)')

print @CharacterData

Answer 6:

select left(NEWID(),5)

这将返回GUID字符串的5个最左边的字符

Example run
------------
11C89
9DB02

Answer 7:

我不是在T-SQL专家，但simpliest方式，我已经使用它就像是：

select char((rand()*25 + 65))+char((rand()*25 + 65))

这产生两个char（AZ，以ASCII 65-90）。

Answer 8:

这里是一个随机的字母数字生成器

print left(replace(newid(),'-',''),@length) //--@length is the length of random Num.

Answer 9:

这为我工作：我需要生成一个ID只有三个随机字母数字字符，但它可以为任何长度可达15个左右的工作。

declare @DesiredLength as int = 3;
select substring(replace(newID(),'-',''),cast(RAND()*(31-@DesiredLength) as int),@DesiredLength);

Answer 10:

对于一个随机的信，你可以使用：

select substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ',
                 (abs(checksum(newid())) % 26)+1, 1)

使用的一个重要区别newid()与rand()是，如果返回多行， newid()分别为每行计算，而rand()是整个查询计算一次。

Answer 11:

我意识到，这是许多优秀的答案，一个老问题。 然而，当我发现这个我还发现由赛义德·哈萨尼TechNet上的一个较新的文章

T-SQL：如何生成随机密码

而解决方案的重点密码，它适用于一般情况。 赛义德致力于通过各种考虑，以达成解决办法。 这是非常有益的。

包含所有的代码块形成文章的脚本是通过单独提供的TechNet库 ，但我会在文章肯定开始。

Answer 12:

我用这个方法是我公司开发只是stipluate你希望能够在输入变量来显示构成特征，你可以定义的长度了。 希望这个格式好，我是新来的堆栈溢出。

IF EXISTS (SELECT * FROM sys.objects WHERE type = 'P' AND object_id = OBJECT_ID(N'GenerateARandomString'))
DROP PROCEDURE GenerateARandomString
GO

CREATE PROCEDURE GenerateARandomString
(
     @DESIREDLENGTH         INTEGER = 100,                  
     @NUMBERS               VARCHAR(50) 
        = '0123456789',     
     @ALPHABET              VARCHAR(100) 
        ='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz',
     @SPECIALS              VARCHAR(50) 
        = '_=+-$£%^&*()"!@~#:', 
     @RANDOMSTRING          VARCHAR(8000)   OUT 

)

AS

BEGIN
    -- Author David Riley
    -- Version 1.0 
    -- You could alter to one big string .e.e numebrs , alpha special etc
    -- added for more felxibility in case I want to extend i.e put logic  in for 3 numbers, 2 pecials 3 numbers etc
    -- for now just randomly pick one of them

    DECLARE @SWAP                   VARCHAR(8000);      -- Will be used as a tempoary buffer 
    DECLARE @SELECTOR               INTEGER = 0;

    DECLARE @CURRENTLENGHT          INTEGER = 0;
    WHILE @CURRENTLENGHT < @DESIREDLENGTH
    BEGIN

        -- Do we want a number, special character or Alphabet Randonly decide?
        SET @SELECTOR  = CAST(ABS(CHECKSUM(NEWID())) % 3 AS INTEGER);   -- Always three 1 number , 2 alphaBET , 3 special;
        IF @SELECTOR = 0
        BEGIN
            SET @SELECTOR = 3
        END;

        -- SET SWAP VARIABLE AS DESIRED
        SELECT @SWAP = CASE WHEN @SELECTOR = 1 THEN @NUMBERS WHEN @SELECTOR = 2 THEN @ALPHABET ELSE @SPECIALS END;

        -- MAKE THE SELECTION
        SET @SELECTOR  = CAST(ABS(CHECKSUM(NEWID())) % LEN(@SWAP) AS INTEGER);
        IF @SELECTOR = 0
        BEGIN
            SET @SELECTOR = LEN(@SWAP)
        END;

        SET @RANDOMSTRING = ISNULL(@RANDOMSTRING,'') + SUBSTRING(@SWAP,@SELECTOR,1);
        SET @CURRENTLENGHT = LEN(@RANDOMSTRING);
    END;

END;

GO

DECLARE @RANDOMSTRING VARCHAR(8000)

EXEC GenerateARandomString @RANDOMSTRING = @RANDOMSTRING OUT

SELECT @RANDOMSTRING

Answer 13:

我碰上了这篇博客文章的第一，然后用下面这样的存储过程，我使用的是目前的一个项目（遗憾的怪异格式）想出了：

CREATE PROCEDURE [dbo].[SpGenerateRandomString]
@sLength tinyint = 10,
@randomString varchar(50) OUTPUT
AS
BEGIN
SET NOCOUNT ON
DECLARE @counter tinyint
DECLARE @nextChar char(1)
SET @counter = 1
SET @randomString = ”

WHILE @counter <= @sLength
BEGIN
SELECT @nextChar = CHAR(48 + CONVERT(INT, (122-48+1)*RAND()))

IF ASCII(@nextChar) not in (58,59,60,61,62,63,64,91,92,93,94,95,96)
BEGIN
SELECT @randomString = @randomString + @nextChar
SET @counter = @counter + 1
END
END
END

Answer 14:

我通过创建一个表，有我想用字符，创建由NEWID从表排序选择字符（）一个视图，然后选择从该视图顶部1个字符这样做在SQL 2000。

CREATE VIEW dbo.vwCodeCharRandom
AS
SELECT TOP 100 PERCENT 
    CodeChar
FROM dbo.tblCharacter
ORDER BY 
    NEWID()

...

SELECT TOP 1 CodeChar FROM dbo.vwCodeCharRandom

然后，你可以简单地从视图拉字符，并根据需要将它们连接起来。

编辑：史蒂芬的反应启发......

select top 1 RandomChar from tblRandomCharacters order by newid()

无需视图（其实我不知道为什么我这样做 - 代码的，从几年前）。 您还可以指定要在表中使用的字符。

Answer 15:

下面有一些基于新的ID。

with list as 
(
    select 1 as id,newid() as val
         union all
    select id + 1,NEWID()
    from    list   
    where   id + 1 < 10
) 
select ID,val from list
option (maxrecursion 0)

Answer 16:

我想我会分享，或回馈社会......这是基于ASCII的，解决的办法是不完美的，但它工作得很好。 享受戈兰B.

/* 
-- predictable masking of ascii chars within a given decimal range
-- purpose: 
--    i needed an alternative to hashing alg. or uniqueidentifier functions
--    because i wanted to be able to revert to original char set if possible ("if", the operative word)
-- notes: wrap below in a scalar function if desired (i.e. recommended)
-- by goran biljetina (2014-02-25)
*/

declare 
@length int
,@position int
,@maskedString varchar(500)
,@inpString varchar(500)
,@offsetAsciiUp1 smallint
,@offsetAsciiDown1 smallint
,@ipOffset smallint
,@asciiHiBound smallint
,@asciiLoBound smallint


set @ipOffset=null
set @offsetAsciiUp1=1
set @offsetAsciiDown1=-1
set @asciiHiBound=126 --> up to and NOT including
set @asciiLoBound=31 --> up from and NOT including

SET @inpString = '{"config":"some string value", "boolAttr": true}'
SET @length = LEN(@inpString)

SET @position = 1
SET @maskedString = ''

--> MASK:
---------
WHILE (@position < @length+1) BEGIN
    SELECT @maskedString = @maskedString + 
    ISNULL(
        CASE 
        WHEN ASCII(SUBSTRING(@inpString,@position,1))>@asciiLoBound AND ASCII(SUBSTRING(@inpString,@position,1))<@asciiHiBound
         THEN
            CHAR(ASCII(SUBSTRING(@inpString,@position,1))+
            (case when @ipOffset is null then
            case when ASCII(SUBSTRING(@inpString,@position,1))%2=0 then @offsetAsciiUp1 else @offsetAsciiDown1 end
            else @ipOffset end))
        WHEN ASCII(SUBSTRING(@inpString,@position,1))<=@asciiLoBound
         THEN '('+CONVERT(varchar,ASCII(SUBSTRING(@Inpstring,@position,1))+1000)+')' --> wrap for decode
        WHEN ASCII(SUBSTRING(@inpString,@position,1))>=@asciiHiBound
         THEN '('+CONVERT(varchar,ASCII(SUBSTRING(@inpString,@position,1))+1000)+')' --> wrap for decode
        END
        ,'')
    SELECT @position = @position + 1
END

select @MaskedString


SET @inpString = @maskedString
SET @length = LEN(@inpString)

SET @position = 1
SET @maskedString = ''

--> UNMASK (Limited to within ascii lo-hi bound):
-------------------------------------------------
WHILE (@position < @length+1) BEGIN
    SELECT @maskedString = @maskedString + 
    ISNULL(
        CASE 
        WHEN ASCII(SUBSTRING(@inpString,@position,1))>@asciiLoBound AND ASCII(SUBSTRING(@inpString,@position,1))<@asciiHiBound
         THEN
            CHAR(ASCII(SUBSTRING(@inpString,@position,1))+
            (case when @ipOffset is null then
            case when ASCII(SUBSTRING(@inpString,@position,1))%2=1 then @offsetAsciiDown1 else @offsetAsciiUp1 end
            else @ipOffset*(-1) end))
        ELSE ''
        END
        ,'')
    SELECT @position = @position + 1
END

select @maskedString

Answer 17:

这使用兰特与像其他的答案中的一个种子，但没有必要提供在每次调用的种子。 提供了它的第一个电话就足够了。

这是我修改后的代码。

IF EXISTS (SELECT * FROM sys.objects WHERE type = 'P' AND object_id = OBJECT_ID(N'usp_generateIdentifier'))
DROP PROCEDURE usp_generateIdentifier
GO

create procedure usp_generateIdentifier
    @minLen int = 1
    , @maxLen int = 256
    , @seed int output
    , @string varchar(8000) output
as
begin
    set nocount on;
    declare @length int;
    declare @alpha varchar(8000)
        , @digit varchar(8000)
        , @specials varchar(8000)
        , @first varchar(8000)

    select @alpha = 'qwertyuiopasdfghjklzxcvbnm'
        , @digit = '1234567890'
        , @specials = '_@#$&'
    select @first = @alpha + '_@';

    -- Establish our rand seed and store a new seed for next time
    set  @seed = (rand(@seed)*2147483647);

    select @length = @minLen + rand() * (@maxLen-@minLen);
    --print @length

    declare @dice int;
    select @dice = rand() * len(@first);
    select @string = substring(@first, @dice, 1);

    while 0 < @length 
    begin
        select @dice = rand() * 100;
        if (@dice < 10) -- 10% special chars
        begin
            select @dice = rand() * len(@specials)+1;
            select @string = @string + substring(@specials, @dice, 1);
        end
        else if (@dice < 10+10) -- 10% digits
        begin
            select @dice = rand() * len(@digit)+1;
            select @string = @string + substring(@digit, @dice, 1);
        end
        else -- rest 80% alpha
        begin
            select @dice = rand() * len(@alpha)+1;

            select @string = @string + substring(@alpha, @dice, 1);
        end

        select @length = @length - 1;   
    end
end
go

Answer 18:

有很多很好的答案，但到目前为止，他们没有允许自定义字符池和工作，作为一个列的默认值。 我希望能够做这样的事情：

alter table MY_TABLE add MY_COLUMN char(20) not null
  default dbo.GenerateToken(crypt_gen_random(20))

所以，我想出了这个。 硬编码数32当心，如果你修改它。

-- Converts a varbinary of length N into a varchar of length N.
-- Recommend passing in the result of CRYPT_GEN_RANDOM(N).
create function GenerateToken(@randomBytes varbinary(max))
returns varchar(max) as begin

-- Limit to 32 chars to get an even distribution (because 32 divides 256) with easy math.
declare @allowedChars char(32);
set @allowedChars = 'abcdefghijklmnopqrstuvwxyz012345';

declare @oneByte tinyint;
declare @oneChar char(1);
declare @index int;
declare @token varchar(max);

set @index = 0;
set @token = '';

while @index < datalength(@randomBytes)
begin
    -- Get next byte, use it to index into @allowedChars, and append to @token.
    -- Note: substring is 1-based.
    set @index = @index + 1;
    select @oneByte = convert(tinyint, substring(@randomBytes, @index, 1));
    select @oneChar = substring(@allowedChars, 1 + (@oneByte % 32), 1); -- 32 is the number of @allowedChars
    select @token = @token + @oneChar;
end

return @token;

end

Answer 19:

有时候，我们需要大量的随机的东西：爱，善良，度假，等我收集了多年来的几个随机生成，而这些都是从皮纳尔戴夫和计算器的答案，我发现一次。 下面参考文献。

--Adapted from Pinal Dave; http://blog.sqlauthority.com/2007/04/29/sql-server-random-number-generator-script-sql-query/
SELECT 
    ABS( CAST( NEWID() AS BINARY( 6)) %1000) + 1 AS RandomInt
    , CAST( (ABS( CAST( NEWID() AS BINARY( 6)) %1000) + 1)/7.0123 AS NUMERIC( 15,4)) AS RandomNumeric
    , DATEADD( DAY, -1*(ABS( CAST( NEWID() AS BINARY( 6)) %1000) + 1), GETDATE()) AS RandomDate
    --This line from http://stackoverflow.com/questions/15038311/sql-password-generator-8-characters-upper-and-lower-and-include-a-number
    , CAST((ABS(CHECKSUM(NEWID()))%10) AS VARCHAR(1)) + CHAR(ASCII('a')+(ABS(CHECKSUM(NEWID()))%25)) + CHAR(ASCII('A')+(ABS(CHECKSUM(NEWID()))%25)) + LEFT(NEWID(),5) AS RandomChar
    , ABS(CHECKSUM(NEWID()))%50000+1 AS RandomID

Answer 20:

在SQL Server 2012+，我们可以合并在一起，（G）的UID的二进制文件，然后执行的base64的成果转化。

SELECT 
    textLen.textLen
,   left((
        select  CAST(newid() as varbinary(max)) + CAST(newid() as varbinary(max)) 
        where   textLen.textLen is not null /*force evaluation for each outer query row*/ 
        FOR XML PATH(''), BINARY BASE64
    ),textLen.textLen)   as  randomText
FROM ( values (2),(4),(48) ) as textLen(textLen)    --define lengths here
;

如果您需要更长的字符串（或者你看到=字符的结果），你需要添加更多+ CAST(newid() as varbinary(max))在子选择。

Answer 21:

所以，我非常喜欢的以上问题的答案，但我一直在寻找的东西，是一个小的性质更随机。 我也想办法明确叫出排除的字符。 下面是使用一个调用视图我的解决方案CRYPT_GEN_RANDOM得到一个加密的随机数。 在我的例子，我只是选择了一个随机数，即8个字节。 请注意，您可以增加此大小，并且还利用功能的种子参数，如果你想。 这里是链接到文件： https://docs.microsoft.com/en-us/sql/t-sql/functions/crypt-gen-random-transact-sql

CREATE VIEW [dbo].[VW_CRYPT_GEN_RANDOM_8]
AS
SELECT CRYPT_GEN_RANDOM(8) as [value];

之所以创建视图是因为CRYPT_GEN_RANDOM不能直接从一个函数调用。

从那里，我创建接受的长度，并且可以含有排除的字符的逗号分隔的字符串的字符串参数的标量函数。

CREATE FUNCTION [dbo].[fn_GenerateRandomString]
( 
    @length INT,
    @excludedCharacters VARCHAR(200) --Comma delimited string of excluded characters
)
RETURNS VARCHAR(Max)
BEGIN
    DECLARE @returnValue VARCHAR(Max) = ''
        , @asciiValue INT
        , @currentCharacter CHAR;

    --Optional concept, you can add default excluded characters
    SET @excludedCharacters = CONCAT(@excludedCharacters,',^,*,(,),-,_,=,+,[,{,],},\,|,;,:,'',",<,.,>,/,`,~');

    --Table of excluded characters
    DECLARE @excludedCharactersTable table([asciiValue] INT);

    --Insert comma
    INSERT INTO @excludedCharactersTable SELECT 44;

    --Stores the ascii value of the excluded characters in the table
    INSERT INTO @excludedCharactersTable
    SELECT ASCII(TRIM(value))
    FROM STRING_SPLIT(@excludedCharacters, ',')
    WHERE LEN(TRIM(value)) = 1;

    --Keep looping until the return string is filled
    WHILE(LEN(@returnValue) < @length)
    BEGIN
        --Get a truly random integer values from 33-126
        SET @asciiValue = (SELECT TOP 1 (ABS(CONVERT(INT, [value])) % 94) + 33 FROM [dbo].[VW_CRYPT_GEN_RANDOM_8]);

        --If the random integer value is not in the excluded characters table then append to the return string
        IF(NOT EXISTS(SELECT * 
                        FROM @excludedCharactersTable 
                        WHERE [asciiValue] = @asciiValue))
        BEGIN
            SET @returnValue = @returnValue + CHAR(@asciiValue);
        END
    END

    RETURN(@returnValue);
END

下面是如何调用该函数的一个例子。

SELECT [dbo].[fn_GenerateRandomString](8,'!,@,#,$,%,&,?');

〜干杯

Answer 22:

这里有一个我想出了今天（因为我不喜欢任何足以现有的答案）。

这一个产生随机串的一个临时表，是基于关闭的newid()而且还支持一个自定义的字符集（所以不止0-9＆AF），定制长度（最多255个，限制是硬编码的，但可以更改），并随机记录的自定义数字。

这里的源代码（希望的评论帮助）：

/**
 * First, we're going to define the random parameters for this
 * snippet. Changing these variables will alter the entire
 * outcome of this script. Try not to break everything.
 *
 * @var {int}       count    The number of random values to generate.
 * @var {int}       length   The length of each random value.
 * @var {char(62)}  charset  The characters that may appear within a random value.
 */

-- Define the parameters
declare @count int = 10
declare @length int = 60
declare @charset char(62) = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'

/**
 * We're going to define our random table to be twice the maximum
 * length (255 * 2 = 510). It's twice because we will be using
 * the newid() method, which produces hex guids. More later.
 */

-- Create the random table
declare @random table (
    value nvarchar(510)
)

/**
 * We'll use two characters from newid() to make one character in
 * the random value. Each newid() provides us 32 hex characters,
 * so we'll have to make multiple calls depending on length.
 */

-- Determine how many "newid()" calls we'll need per random value
declare @iterations int = ceiling(@length * 2 / 32.0)

/**
 * Before we start making multiple calls to "newid", we need to
 * start with an initial value. Since we know that we need at
 * least one call, we will go ahead and satisfy the count.
 */

-- Iterate up to the count
declare @i int = 0 while @i < @count begin set @i = @i + 1

    -- Insert a new set of 32 hex characters for each record, limiting to @length * 2
    insert into @random
        select substring(replace(newid(), '-', ''), 1, @length * 2)

end

-- Now fill the remaining the remaining length using a series of update clauses
set @i = 0 while @i < @iterations begin set @i = @i + 1

    -- Append to the original value, limit @length * 2
    update @random
        set value = substring(value + replace(newid(), '-', ''), 1, @length * 2)

end

/**
 * Now that we have our base random values, we can convert them
 * into the final random values. We'll do this by taking two
 * hex characters, and mapping then to one charset value.
 */

-- Convert the base random values to charset random values
set @i = 0 while @i < @length begin set @i = @i + 1

    /**
     * Explaining what's actually going on here is a bit complex. I'll
     * do my best to break it down step by step. Hopefully you'll be
     * able to follow along. If not, then wise up and come back.
     */

    -- Perform the update
    update @random
        set value =

            /**
             * Everything we're doing here is in a loop. The @i variable marks
             * what character of the final result we're assigning. We will
             * start off by taking everything we've already done first.
             */

            -- Take the part of the string up to the current index
            substring(value, 1, @i - 1) +

            /**
             * Now we're going to convert the two hex values after the index,
             * and convert them to a single charset value. We can do this
             * with a bit of math and conversions, so function away!
             */

            -- Replace the current two hex values with one charset value
            substring(@charset, convert(int, convert(varbinary(1), substring(value, @i, 2), 2)) * (len(@charset) - 1) / 255 + 1, 1) +
    --  (1) -------------------------------------------------------^^^^^^^^^^^^^^^^^^^^^^^-----------------------------------------
    --  (2) ---------------------------------^^^^^^^^^^^^^^^^^^^^^^11111111111111111111111^^^^-------------------------------------
    --  (3) --------------------^^^^^^^^^^^^^2222222222222222222222222222222222222222222222222^------------------------------------
    --  (4) --------------------333333333333333333333333333333333333333333333333333333333333333---^^^^^^^^^^^^^^^^^^^^^^^^^--------
    --  (5) --------------------333333333333333333333333333333333333333333333333333333333333333^^^4444444444444444444444444--------
    --  (6) --------------------5555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555^^^^----
    --  (7) ^^^^^^^^^^^^^^^^^^^^66666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666^^^^

            /**
             * (1) - Determine the two hex characters that we'll be converting (ex: 0F, AB, 3C, etc.)
             * (2) - Convert those two hex characters to a a proper hexadecimal (ex: 0x0F, 0xAB, 0x3C, etc.)
             * (3) - Convert the hexadecimals to integers (ex: 15, 171, 60)
             * (4) - Determine the conversion ratio between the length of @charset and the range of hexadecimals (255)
             * (5) - Multiply the integer from (3) with the conversion ratio from (4) to get a value between 0 and (len(@charset) - 1)
             * (6) - Add 1 to the offset from (5) to get a value between 1 and len(@charset), since strings start at 1 in SQL
             * (7) - Use the offset from (6) and grab a single character from @subset
             */

            /**
             * All that is left is to add in everything we have left to do.
             * We will eventually process the entire string, but we will
             * take things one step at a time. Round and round we go!
             */

            -- Append everything we have left to do
            substring(value, 2 + @i, len(value))

end

-- Select the results
select value
from @random

这不是一个存储过程，但它不会是很难变成一个。 这也是不慢的窘况（我花了-0.3秒，产生1000个结果长度60，这比我会永远个人需要的），这是我从所有的字符串突变我做的最初关注的问题之一。

这里主要的外卖是，我并不想创建自己的随机数生成器，和我的字符集不受限制。 我只是使用随机发生器SQL有（我知道有rand()但是这不是很大的表结果）。 希望这种方法娶两种答案在这里，从过于简单（即只newid()和过于复杂（即定制随机数的算法）。

这也是短期（减去评论），和易于理解的（至少对我来说），它总是在我的书有加。

然而，这种方法不能是种子，所以这将真正随机的，每次是，你将无法复制相同的一组数据，其可靠性的任何手段。 该任择议定书没有列出作为一项要求，但我知道，有些人寻找之类的事情。

我知道我迟到了这里，但我希望有人会发现这很有用。

Answer 23:

这是非常simply.use和享受。

CREATE VIEW [dbo].[vwGetNewId]
AS
SELECT        NEWID() AS Id

Creat FUNCTION [dbo].[fnGenerateRandomString](@length INT = 8)
RETURNS NVARCHAR(MAX)
AS
BEGIN

DECLARE @result CHAR(2000);

DECLARE @String VARCHAR(2000);

SET @String = 'abcdefghijklmnopqrstuvwxyz' + --lower letters
'ABCDEFGHIJKLMNOPQRSTUVWXYZ' + --upper letters
'1234567890'; --number characters

SELECT @result =
(
    SELECT TOP (@length)
           SUBSTRING(@String, 1 + number, 1) AS [text()]
    FROM master..spt_values
    WHERE number < DATALENGTH(@String)
          AND type = 'P'
    ORDER BY
(
    SELECT TOP 1 Id FROM dbo.vwGetNewId
)   --instead of using newid()
    FOR XML PATH('')
);

RETURN @result;

END;

文章来源: Generating random strings with T-SQL