ALTER function CharReversal(@inputstring varchar(max))
returns varchar(max)
WITH SCHEMABINDING
AS
BEGIN
  DECLARE @i int, 
          @Results varchar(max)
  SET @Results=''
  SET @i = 1
  WHILE @i <= DATALENGTH(@inputstring)
    BEGIN
      SET @Results = SUBSTRING(@inputstring,@i,1) + @Results
      SET @i=@i + 1
    END
RETURN @Results
END


select dbo.CharReversal('abc123xyz')
--Results:zyx321cba

/* TSQL Challenge #3
    Tested on SQL Server 2008
    By RBarryYoung, March 28, 2009
*/
DECLARE @t TABLE( ID INT IDENTITY, data VARCHAR(MAX))
INSERT INTO @t(data) SELECT 'Jacob'
INSERT INTO @t(data) SELECT 'Sebastian'

;WITH cteReverseRecur as (
    Select ID
     , RIGHT( data, 1 ) as RevStr
     , LEFT( data, LEN([data])-1 ) as RemStr
     From @t
  UNION ALL
    Select ID
     , RevStr + RIGHT( RemStr, 1 )
     , Left( RemStr, LEN(RemStr)-1 )
     From cteReverseRecur
     Where RemStr > '')
SELECT ID, RevStr as data
 From cteReverseRecur
 Where RemStr = '';

declare @Str varchar(100), @StrRev varchar(100);

select @Str = 'able was I ere I saw elba';

select @StrRev = coalesce(@StrRev + substring(@Str, number, 1), substring(@Str, number, 1))
from dbo.Numbers
where number between 1 and len(@Str)
order by number desc;

select @Str, @StrRev;