help with sql

[Charllotte Hurt <CHurt@YAR.MIRACOSTA.CC.CA.US>]

I am working with an sql statement which I need to modify in order to pick up 
additional information in another table.  (The tables involved are from the 
PeopleSoft Student Administration product and this sql statement is a view.)  
The outcome I want from this is all the fields currently being selected; but, 
in addition, I need the descr254a field from the rq_grp_tbl for those courses 
which have a rqrmrnt_group and also those courses which don't have a 
rqrmnt_group.  The sql below is the original with my additions in bold.  I also 
have put crse_ids to simplify my testing, one has a rqrmnt_group and one does 
not.  My problem is that I receive one row with all the necessary information 
for the course id which has the rqrmnt_group, but for the one which doesn't I 
am getting back every row from the rq_grp_tbl (because of my not exists).  I 
only want one row returned for each course_id in my select.  I am getting back 
243 rows, one for the course with the rqrmnt_group and 242 rows !
for the one which has no rqrmnt_group (242 rows is the totat count of the 
rq_grp_tbl).

I would really appreciate some help on this.  Any suggestions?  I need to do 
this in the sql--not in an sqr.  (Sqr would allow loops=1).

Thanks in advance for your assistance.

SELECT
A.CRSE_ID
,A.EFFDT
,B.INSTITUTION
,B.SUBJECT
,B.CATALOG_NBR
,A.EFF_STATUS
,A.UNITS_MINIMUM
,A.UNITS_MAXIMUM
,A.COMPONENT
,A.COURSE_TITLE_LONG
,C.DESCRFORMAL
,D.DESCR
,E.XLATLONGNAME
,A.DESCRLONG
,f.descr254a
,b.rqrmnt_group
FROM
PS_CRSE_CATALOG A,
PS_CRSE_OFFER B,
PS_SUBJECT_TBL C,
PS_INSTITUTION_TBL D,
XLATTABLE E,
ps_rq_grp_tbl f
WHERE A.CRSE_ID = B.CRSE_ID AND
a.crse_id in ('001750','000322') and
A.EFFDT =
   ( SELECT MAX(Z.EFFDT)
     FROM PS_CRSE_CATALOG Z
     WHERE A.CRSE_ID = Z.CRSE_ID
       AND Z.EFFDT <= sysdate)
AND
A.EFF_STATUS = 'A' AND
A.EFFDT = B.EFFDT AND
B.CATALOG_PRINT = 'Y' AND
B.INSTITUTION = C.INSTITUTION AND
C.EFFDT =
   ( SELECT MAX(X.EFFDT)
     FROM PS_SUBJECT_TBL X
     WHERE C.INSTITUTION = X.INSTITUTION
       AND C.SUBJECT = X.SUBJECT
       AND X.EFFDT <= sysdate) AND
B.INSTITUTION = D.INSTITUTION AND
D.EFFDT =
   ( SELECT MAX(Y.EFFDT)
     FROM PS_INSTITUTION_TBL Y
     WHERE D.INSTITUTION = Y.INSTITUTION
       AND Y.EFFDT <= sysdate) AND
B.SUBJECT = C.SUBJECT AND
B.INSTITUTION = D.INSTITUTION AND
E.FIELDNAME = 'COMPONENT' AND
E.LANGUAGE_CD =
   (SELECT LANGUAGE_CD FROM PSOPTIONS)
AND
A.COMPONENT = E.FIELDVALUE AND
E.EFFDT =
   ( SELECT MAX(W.EFFDT)
     FROM XLATTABLE W
     WHERE E.FIELDNAME = W.FIELDNAME
       AND E.LANGUAGE_CD = W.LANGUAGE_CD
       AND E.FIELDVALUE  = W.FIELDVALUE
       AND W.EFFDT <= sysdate)
and (b.rqrmnt_group = f.rqrmnt_group
and f.effdt  =
( SELECT MAX(f1.EFFDT)
     FROM ps_rq_grp_tbl f1
     WHERE f1.rqrmnt_group = f.rqrmnt_group
       AND f1.EFFDT <= sysdate)
and f.eff_status = 'A' or
(not exists (select 'x' from ps_rq_grp_tbl f2
where f2.rqrmnt_group = b.rqrmnt_group)));