Does this help you out?
declare @STR varchar(8000);
set @STR = 'qothobnslfdnoweavnivmnqpwf';
;WITH
TENS (N) AS (SELECT 0 UNION ALL SELECT 0 UNION ALL SELECT 0 UNION ALL
SELECT 0 UNION ALL SELECT 0 UNION ALL SELECT 0 UNION ALL
SELECT 0 UNION ALL SELECT 0 UNION ALL SELECT 0 UNION ALL SELECT 0),
THOUSANDS (N) AS (SELECT 1 FROM TENS t1 CROSS JOIN TENS t2 CROSS JOIN TENS t3),
MILLIONS (N) AS (SELECT 1 FROM THOUSANDS t1 CROSS JOIN THOUSANDS t2),
TALLY (N) AS (SELECT ROW_NUMBER() OVER (ORDER BY (SELECT 0)) FROM MILLIONS)
SELECT N,
LetterAsPosition = substring(@str, N, 1),
AsciiAtPosition = ascii(substring(@str, N, 1))
FROM TALLY
WHERE N <= datalength(@str)
ORDER BY N;
Wayne
Microsoft Certified Master: SQL Server 2008
Author - SQL Server T-SQL Recipes