Multiple conditions on a where clause column in SQL Server - sql-server

Question

I had written a stored procedure where it needs to execute the where condition based on the parameter values as follows :
alter proc sp_cc_get_grn_details
(
#vendor_id varchar(100) = null,
#po_id int = null,
#invoice_id int = null,
#invoice_from_dt datetime2 = null,
#invoice_to_dt datetime2 = null,
#grn_status int = null
)
AS
BEGIN
SELECT vd.vendor_id,vd.vendor_name,id.po_id,id.invoice_id,id.invoice_amount,id.invoice_date,
CASE
WHEN id.grn_status = 0 THEN 'Pending'
WHEN id.grn_status = 1 THEN 'Completed'
ELSE 'Pending'
END AS grn_status into #Tempres
FROM
vendor_details vd JOIN po_details pd on vd.vendor_id = pd.vendor_id
join invoice_details id on id.po_id = pd.po_id
WHERE
(#vendor_id is null or #vendor_id = '' or vd.vendor_id = #vendor_id) AND
(#po_id is null or #po_id = '' or id.po_id = #po_id) AND
(#invoice_id is null or #invoice_id = '' or id.invoice_id = #invoice_id) and
(id.invoice_date BETWEEN #invoice_from_dt AND #invoice_to_dt)
if(#grn_status = 1)
select * from #Tempres where grn_status = 'Completed';
else if(#grn_status = 2)
select * from #Tempres where grn_status = 'Pending';
else
select * from #Tempres;
drop table #Tempres;
END
The above procedure is working. But what's my need is, Is there any way to make "#grn_status" parameter too in the where clause instead of writing with if & else.

Answer 1

something like this would work
where #grn_Status not in (1, 2) or
grn_status =
case #grn_status
when 1 then 'Completed'
when 2 then 'Pending'
end