DECLARE @s varchar(100);
SELECT @s = 'Und Was Habe Ich Damit Zu Tun?';
SELECT
x.OnlyInitials
FROM
(SELECT
SUBSTRING(@s, N.Number, 1)
FROM
dbo.Number N
WHERE
N.Number BETWEEN 1 AND LEN(@s) AND
ASCII(SUBSTRING(@s, N.Number, 1)) BETWEEN 65 AND 90
FOR XML PATH('')) AS x(OnlyInitials);
OnlyInitials
------------
UWHIDZT
(1 row(s) affected