SQL Create View and using it in Function - sql

Question

I have the following function and I need to take out the SELECT part and create a separate view.
CREATE FUNCTION dbo.dbf_get_penalty_points
( #pn_seq_party_id NUMERIC(18),
#pv_penalty_points_code CHAR(1) = 'Y') -- Use 'N' for total points, otherwise will return Current Penalty Points
RETURNS NUMERIC(18,0)
AS
BEGIN
DECLARE #n_penalty_points NUMERIC(18),
#d_latest_points_date DATETIME
SELECT #d_latest_points_date = dbo.dbf_trunc_date(DateAdd(mm, - Abs(Convert(NUMERIC(18,0),dbo.dbf_get_sys_param('CMS2', 'PP_MONTHS'))), GetDate()))
SELECT #n_penalty_points = IsNull(Sum(penalty_points_amount),0)
FROM dbo.ar_penalty_point WITH(NOLOCK)
WHERE seq_party_id = #pn_seq_party_id
AND 1 = CASE
WHEN #pv_penalty_points_code = 'N' THEN 1
WHEN #pv_penalty_points_code = 'Y' AND added_date >= #d_latest_points_date AND reset_date IS NULL THEN 1
ELSE 0
END
RETURN #n_penalty_points
END
GO
SET QUOTED_IDENTIFIER OFF
GO
GRANT EXECUTE ON dbo.dbf_get_penalty_points TO standard
GO
I have tried and got this,
SELECT SUM(CASE WHEN added_date >=dbo.dbf_trunc_date(DateAdd(mm, - Abs(Convert(NUMERIC(18,0),dbo.dbf_get_sys_param('CMS2', 'PP_MONTHS'))), GetDate()))
AND reset_date IS NULL THEN 1
ELSE 0) current_points,
IsNull(Sum(penalty_points_amount),0) total_points,
seq_party_id
FROM dbo.ar_penalty_point WITH(NOLOCK)
GROUP BY seq_party_id
Now I need to get rid of
dbo.dbf_trunc_date(DateAdd(mm, - Abs(Convert(NUMERIC(18,0),dbo.dbf_get_sys_param('CMS2', 'PP_MONTHS'))), GetDate()))
From the SELECT part of the query. I am struck is there a better way to write my view ?
EDIT
The objective is to create a view that returns total_points and current_points. For better understanding refer the CREATE part following
CREATE FUNCTION dbo.dbf_get_penalty_points
( #pn_seq_party_id NUMERIC(18),
#pv_penalty_points_code CHAR(1) = 'Y') -- Use 'N' for total points, otherwise will return Current Penalty Points
Refer to -- Use 'N' for total points, otherwise will return Current Penalty Points in the comments

Answer 1

This is what I came up with
SELECT SUM(CASE WHEN (t.added_date >= t.target_date
AND t.reset_date IS NULL) THEN 1
ELSE 0 END) current_points,
IsNull(Sum(t.penalty_points_amount),0) total_points,
t.seq_party_id
FROM (
SELECT dbo.dbf_trunc_date(DateAdd(mm, - Abs(Convert(NUMERIC(18,0),dbo.dbf_get_sys_param('CMS2', 'PP_MONTHS'))), GetDate())) as target_date,
u.reset_date, u.penalty_points_amount,u.seq_party_id,u.added_date FROM
dbo.ar_penalty_point as u ) as t GROUP BY t.seq_party_id