I have written following query for a stored procedure:
SELECT
M.ProgramCode,
M.MeetingCode,


CASE
WHEN MA.AttendeeType = 1 THEN 'Participant'
WHEN MA.AttendeeType = 2 THEN 'Speaker/Faculty'

END AS AttendeeType,
Count(A.AttendeeID) as NoofRSVP,
COUNT(CASE WHEN MA.Status=4 THEN 'present' END) as NoofAttendee


FROM
Programs P
INNER
JOIN eCDRReservations M
ON P.SubCompanyCode = M.SubCompanyCode
AND P.ProgramCode = M.ProgramCode
left outer
JOIN MeetingAttendees MA
ON M.ReservationID = MA.MeetingID
and MA.AttendeeType = 1
left outer
JOIN Attendees A
ON MA.AttendeeID = A.AttendeeID
and MA.AttendeeType = 1
left outer
JOIN Regions R
ON MA.RegionCode = R.RegionCode
WHERE
P.SubCompanyCode = @SubCompanyCode AND
P.ProgramCode = @ProgramCode AND
(MA.status = 2 OR MA.status = 4)

this query returns following values:
ProgramCode, MeetingCode, AttendeeType, NoofRSVP, NoofAttendee

In this query I have used MA.AttendeeType = 1 condition in my joins, 1 represent 'Participant' in the table, I am counting only 'Participants' here.

But it wont return any values if there is no Participant for some meeting, means Meeting is present in Programs and eCDRReservations table but there is no Attendeetype=1 in MeetingAttendees table for that meeting.

My task is, I have to modify the query in such a way so that it return 0 as NoofRSVP and 0 as NoofAttendee for all the meetings where there is no Participant. I have to keep all the where clauses too.

I don't want to pretend to be an expert, and I also don't want to pretend that I fully understand the entire query and the existing data, however, the fact that you're doing a left outer join on MeetingAttendees probably is the reason why you're not getting rows back where there are zero participants. I would try doing a different join (full outer?) until I received the data needed, then add more conditions to the where clause until I get exactly what I want.