SQL SERVER 2008 TVF OR CHARINDEX to search column with comma
You need a split TVF on both sides to make it a JOIN

SELECT DISTINCT
   M.ID
FROM
   MyTable M
   CROSS APPLY
   dbo.SomeSplitTVF(M.Blahcolumn) M2
   JOIN
   dbo.SomeSplitTVF(@parameter) P ON M2.value = P.value


There are several solutions for "dbo.SomeSplitTVF" on SO, but you could start with this article by our own Aaron Bertrand