Fulltext-search with field as searchvalue

Hi
I have the following code:

SELECT *,
(SELECT TOP 1 Datum FROM foOfferte_M1 B 
WHERE Kundennummer = 5 and B.Baustelle = A.Baustelle 
ORDER BY datum DESC) AS DatumOfferte
FROM foBaustellen_M1 A WHERE KundenLaufnummer = 5

Select allOpen in new window

It works but it is very slow. The field Baustelle is NTEXT-datatype. I tried to create a fulltextindex but this doesn't speed up the query.

is there another way to speed up or do query that data?
Thanks, Peter