Getting same results without inline view

Question

Hi gurus,
My database version is 10.2.0.4.0.
I have a couple of tables as follows:
CREATE TABLE xxgroups(group_number NUMBER, description VARCHAR2(30));
INSERT INTO xxgroups VALUES(1,'Group 1');
INSERT INTO xxgroups VALUES(2,'Group 2');
INSERT INTO xxgroups VALUES(3,'Group 3');
INSERT INTO xxgroups VALUES(4,'Group 4');
INSERT INTO xxgroups VALUES(5,'Group 5');
CREATE TABLE xxgroup_persons(group_number NUMBER, person_number NUMBER, first_name VARCHAR2(30), last_name VARCHAR2(30));
INSERT INTO xxgroup_persons VALUES(1, 1, 'John', 'Smith');
INSERT INTO xxgroup_persons VALUES(1, 2, 'James', 'Smith');
INSERT INTO xxgroup_persons VALUES(1, 3, 'Joe', 'William');
INSERT INTO xxgroup_persons VALUES(2, 4, 'Julien', 'Ford');
INSERT INTO xxgroup_persons VALUES(2, 5, 'James', 'Kelly');
INSERT INTO xxgroup_persons VALUES(3, 6, 'Francis', 'Smith');
INSERT INTO xxgroup_persons VALUES(5, 7, 'Jerry', 'Ford');
INSERT INTO xxgroup_persons VALUES(5, 8, 'Alfred', 'Willis');
INSERT INTO xxgroup_persons VALUES(5, 9, 'Jon', 'Preston');
COMMIT;I'd like to get a query to return for each group, the person with lower person_number (if no person assigned to the group, then the query should still return the group with empty person). I know I can do it using for instance:
SELECT group_number, person_number, first_name, last_name
FROM (SELECT a.group_number, b.person_number, b.first_name, b.last_name
           , RANK() OVER (PARTITION BY a.group_number ORDER BY person_number) person_order
      FROM xxgroups a, xxgroup_persons b
      WHERE a.group_number = b.group_number (+)
WHERE person_order = 1
ORDER BY group_number;
GROUP_NUMBER PERSON_NUMBER FIRST_NAME                     LAST_NAME
           1             1 John                           Smith
           2             4 Julien                         Ford
           3             6 Francis                        Smith
           4
           5             7 Jerry                          Fordbut would it be possible to get the same results without using inline view?
Thanks.

Answer 1

You could try this the KEEP function:
scott@orapdt>  SELECT a.group_number,
  2         min(b.person_number) as person_number,
  3         min(b.first_name) keep (dense_rank first order by person_number) as first_name,
  4         min(b.last_name) keep (dense_rank first order by person_number) as last_name      
  5  FROM xxgroups a, xxgroup_persons b
  6  WHERE a.group_number = b.group_number (+)
  7  group by a.group_number;
GROUP_NUMBER PERSON_NUMBER FIRST_NAME                     LAST_NAME
           1             1 John                           Smith
           2             4 Julien                         Ford
           3             6 Francis                        Smith
           4
           5             7 Jerry                          Ford
5 rows selected.