sql server 生成随机字符串 如: 32U523

--USE [PaymentService]
GO

/****** Object:  StoredProcedure [dbo].[sp_CreateRandomInviteCode]    Script Date: 2016/1/18 9:11:20 ******/
DROP PROCEDURE [dbo].[sp_CreateRandomInviteCode]
GO

/****** Object:  StoredProcedure [dbo].[sp_CreateRandomInviteCode]    Script Date: 2016/1/18 9:11:20 ******/
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO


/*
    
   DECLARE  @return_value int,
         @InviteCode nvarchar(max)

   EXEC  @return_value = [dbo].[sp_CreateRandomInviteCode]
         @DigitLength = 5,
         @InviteCode = @InviteCode OUTPUT


   SELECT   @InviteCode as N'@InviteCode'


   --SELECT '|' + @InviteCode + '|' as N'@InviteCode'

   --SELECT 'Return Value' = @return_value

   --select char(65)
   --select char(90)
   
   --SELECT CHAR(65 + FLOOR(RAND()*26))

   --select  FLOOR(RAND()*5)

*/



CREATE proc [dbo].[sp_CreateRandomInviteCode](   
   @DigitLength INT=NULL,   
   @InviteCode VARCHAR(MAX)  output
)
AS
BEGIN
   DECLARE @INDEX INT    
   DECLARE @SQL NVARCHAR(MAX)
   DECLARE @RowCounts int
   DECLARE @BOOLBIT BIT  
   DECLARE @RandomStr NVARCHAR(MAX)
   DECLARE @RandomNum int

   DECLARE @randomLetter varchar(1)
   DECLARE @randomLetterPosition INT

   SET @BOOLBIT=1
   SET @RandomStr=''
   SET @INDEX=0

   IF(@DigitLength IS NULL OR @DigitLength<=0)
      SET @DigitLength=1

   SELECT @randomLetter= CHAR(65 + FLOOR(RAND()*26))
   SELECT @randomLetterPosition= FLOOR(RAND()* @DigitLength )
 
   WHILE @BOOLBIT=1
   BEGIN
      WHILE @INDEX<@DigitLength
         BEGIN                  
           SET @RandomStr=@RandomStr+CONVERT(nvarchar, FLOOR(RAND()*10))      
           SET @INDEX=(@INDEX+1)
         END
    
      IF(@randomLetterPosition=0)
          SET @InviteCode=@randomLetter + @RandomStr    
      ELSE
          SET @InviteCode=SUBSTRING(@RandomStr,1,@randomLetterPosition) 
            + @randomLetter + SUBSTRING(@RandomStr,@randomLetterPosition,@DigitLength - @randomLetterPosition)
 
      IF(EXISTS(SELECT * FROM DBO.[DoctorProfile] WHERE InviteCode=@RandomStr))
         BEGIN
            SET @INDEX=0   
           SET @RandomStr=''          
         END
      ELSE
         BEGIN
             SET @BOOLBIT=0             
         END
    
   END    

END

GO

执行结果：