I would diffently do the join. You can either use the XML I provided or a udf. I would prefer the xml though. I dont know how the performance will differ but XML get parsed extremely fast in 2005.

DECLARE @x XML

SET @x = '<i>' + REPLACE( @IDString, ',', '</i><i>') + '</i>'

SELECT *

FROM MyTable a

INNER JOIN

(SELECT x.i.value('.', 'VARCHAR(7)')

FROM @x.nodes('//i') x(i)) b

ON a.ID = b.ID

Additionally, I dont know how you create your delmited string but XML can also do this very, very quickly. See below:

DECLARE @IDString VARCHAR(MAX)

SET @IDString =

(SELECT (ID) + ','

FROM MYTABLE

--WHERE FILTER CAN GO HERE

FOR XML PATH(''))