searching with different paramater

Question

hello brother

i am searching in database i have passing the multiple paramater  

and all the paramater they are searching but the rollnumber is not working 

my code is below

ALTER PROCEDURE [School].[SurcheStudent]

(

@StudentID INT=null,

@ClassAdmitted_ID INT=null,

@Section int=null,

--@IsActive bit=null,

@StudentRegNo varchar(50)=null,

@StudentName varchar(50)=null,

@StudentFname varchar(50)=null,

@RollNo int=null

)

AS

BEGIN

--DECLARE @IsActive int

--if @IsActive=1

--Begin

SELECT ST.StudentID ,ST.StudentName,St.FatherName,St.FatherCNIC,St.StudentAddress,SCM.CurrentClass_ID,SCM.CurrentSection_ID,

SCM.RollNumber,

ST.Account_ID,

ST.StudentRegNo

FROM School.StudentInformation ST INNER JOIN School.StudentClassMapping SCM ON ST.StudentID=Scm.Student_ID

WHERE SCM.CurrentClass_ID=@ClassAdmitted_ID AND SCM.CurrentSection_ID=@Section

AND ST.StudentName LIKE '%'+ISNULL(@StudentName,St.StudentName)+'%'AND ST.FatherName LIKE '%'+ISNULL(@StudentFname,St.FatherName)+'%' AND RollNo=isnull(@RollNo,SCM.RollNumber)

AND ST.StudentID=ISNULL(@StudentID,St.StudentID) AND ST.StudentRegNo LIKE '%'+@StudentRegNo+'%' AND ST.IsActive=1

END