六位随机数目字为何产生不了？各位老大看看什么问_Sql Server

六位随机数字为何产生不了？各位老大看看什么问
     declare @nLen int;
     declare @VerifyCode varchar(10);
     declare @nCount int;
     set @nLen = 6;
     set @nCount = 1;
     while @nCount < @nLen
      begin
        set @VerifyCode = @VerifyCode + CHAR(ROUND(RAND() * 9 + 48,0));
        set @nCount = @nCount + 1;
      end
------解决思路----------------------

     declare @nLen int;
     declare @VerifyCode varchar(10);
     declare @nCount int;
     set @nLen = 6;
     set @nCount = 1;
     Set @VerifyCode = N''
     while @nCount < @nLen
      begin
        set @VerifyCode = @VerifyCode + CHAR(ROUND(RAND() * 9 + 48,0));
        set @nCount = @nCount + 1;
      end
      
     Select @VerifyCode