SELECT DISTINCT SubjectID INTO #Subject FROM tblSetMarks ORDER BY SubjectID  
                 DECLARE @cols NVARCHAR(4000)  
                 SELECT @cols= ISNULL(@cols + ',','') + QUOTENAME(SubjectID) FROM (SELECT DISTINCT SubjectID FROM tblSetMarks ) AS Course 
                 DECLARE @qry NVARCHAR(4000) 
                 SET @qry =  
                N'SELECT *
				FROM (
					  SELECT t.AdmissionNo,t.ReferenceNo,t.SName,t.FName,t2.Marks,t2.[SubjectID]
					  FROM tblStdReg t 
					  FULL OUTER JOIN tblSetMarks t2 inner join tblDefSubject as ds on t2.SubjectID=ds.SubjectID
					  ON t.AdmissionNo = t2.AdmissionNo 
					  
					  )  p
			  PIVOT(Max(Marks) FOR [SubjectID] IN (' +@cols+ ') where ClassID=15) AS pvt '
                 
EXEC(@qry)
DROP TABLE #Subject
This display data of all students. I want to display just Class one student data so how to use where clause in this pivot query. table structure is 
Student : StuID, SName,FName
                1         abc     sky
Marks : StuID,Class,Subject,Marks
               1       One    Eng    26
                2      One     Urdu  20