Is there such a thing has arrays in tsql?

I'm have a stored procedure that iterates through a list of numbers and adds an item for each number (user id) some of these ids are duplicates which is fine even necessary for the first part of my query but for the last I need to ensure that no duplicates id's are passed to the stored procedure, in this case called 'spInsertForBackupNote'. My thoughts here was to do something like this:

SET @Note_Buffer = @UserID -- @Note_Buffer being some kind of array?

IF @Note_Buffer = @UserID -- If its been added to the buffer we dont execute sp
BEGIN
Do Nothing here
END

ELSE

BEGIN
EXECUTE spInsertForBackupNote @FK_UserID, @FK_NoteID
END

I know this would never work because it would always be false since I just added the same userid to the buffer that I want to add. But I think you see my problem. I know it should be an easy one but my TSQL is limited. I've posted the whole sp. Hope someone can help.

CREATE PROCEDURE spInsertAssignedNotesByList
@FK_UserIDList NVARCHAR(4000) = NULL,
@FK_NoteIDList NVARCHAR(4000) = NULL,
@By_Who INT,
@UserID INT

AS
SET NOCOUNT ON

DECLARE @Length INT
DECLARE @Note_Length INT
DECLARE @Note_Buffer INT

DECLARE @FirstUserIDWord NVARCHAR(4000)
DECLARE @FirstNoteIDWord NVARCHAR(4000)

DECLARE @FK_UserID INT
DECLARE @FK_NoteID INT

SELECT @Length = DATALENGTH(@FK_UserIDList )
SELECT @Note_Length = DATALENGTH(@FK_NoteIDList )

DECLARE @TempFK_NoteIDList NVARCHAR(4000) --= NULL
DECLARE @Temp_NoteLength INT

SET @TempFK_NoteIDList = @FK_NoteIDList
SET @Temp_NoteLength = DATALENGTH(@FK_NoteIDList )


-- IF @Length > @Note_Length -- If we have more users than notes

BEGIN

WHILE @Length > 0
BEGIN

IF @Length > 0

EXECUTE @Length = PopFirstWord @FK_UserIDList OUTPUT, @FirstUserIDWord OUTPUT
SELECT @FK_UserID = CONVERT(INT, @FirstUserIDWord)

IF @Length > 0
BEGIN

SET @FK_NoteIDList = @TempFK_NoteIDList
SET @Note_Length = @Temp_NoteLength

WHILE @Note_Length > 0
BEGIN
EXECUTE @Note_Length = PopFirstWord @FK_NoteIDList OUTPUT, @FirstNoteIDWord OUTPUT
SELECT @FK_NoteID = CONVERT(INT, @FirstNoteIDWord)

IF @Note_Length > 0
EXECUTE spInsertAssignedNoteDetail @FK_UserID, @FK_NoteID


SET @Note_Buffer = @UserID
EXECUTE spInsertForBackupNote @FK_UserID, @FK_NoteID, @By_Who, @UserID -- NEW HERE
END
END

END
END



--------------------------------------------------
GO