Need help in understanding a stored proc

UPDATE GuestStayStatistics
SET
AvgLOS = ISNULL(gss.SumLOS*1.00/gss.TotalStays,0),
AvgGuestCount = ISNULL(gss.SumGuestCount*1.00/gss.TotalStays,0),
AvgRevPerStay = ISNULL(gss.SumTotalActualRevenue/gss.TotalStays,0),

FROM (
Select
ProfileId, PropertyCode, IsActualRecord,
sum(case
when gss.ReservationStatus not in ('CANCELED', 'NOSHOW','WAITLIST') then Nights
else NULL
end) SumLOS,

sum(case
when gss.ReservationStatus not in ('CANCELED', 'NOSHOW','WAITLIST') then GuestCount
else NULL
end) SumGuestCount,

can i use the following code in oracle for the same function

AS

sql_status number;
col1 gueststaystatistics.AVGLOS%TYPE;
col2 gueststaystatistics.AVGGUESTCOUNT%TYPE;
col3 gueststaystatistics.AVGREVPERSTAY%TYPE;

CURSOR c1 IS
SELECT gstat.ROWID,
gss.AVGLOS,gss.AVGGUESTCOUNT,gss.AVGREVPERSTAY FROM (SELECT
profileid,
propertycode,
isactualrecord,
AVG(case
when gss.ReservationStatus not in ( 'CANCELED' , 'NOSHOW' , 'WAITLIST' ) then Nights * 1.00
else 0
end) AVGLOS,
AVG(case
when gss.ReservationStatus not in ( 'CANCELED' , 'NOSHOW' , 'WAITLIST' ) then GuestCount * 1.00
else 0
end) AVGGUESTCOUNT,
AVG(case
when gss.ReservationStatus not in ( 'CANCELED' , 'NOSHOW' , 'WAITLIST' ) then
case
when gss.TotalActualRevenue = 0 THEN NVL(gss.TotalRoomRevenue, 0)
ELSE NVL(gss.TotalActualRevenue, 0)
END
else 0
end) AVGREVPERSTAY,

Please could you clarify what you want to achieve here. Are you trying to convert SQL server stored procedure into Oracle stored procedure? I don't understand what exactly your procedure is trying to do.