[8i] Need help with full outer join combined with a cross-join....

Question

I can't figure out how to combine a full outer join with another type of join ... is this possible?
Here's some create table and insert statements for some basic sample data:
CREATE TABLE     my_tab1
(     record_id     NUMBER     NOT NULL     
,     workstation     VARCHAR2(4)
,     my_value     NUMBER
     CONSTRAINT my_tab1_pk PRIMARY KEY (record_id)
INSERT INTO     my_tab1
VALUES(1,'ABCD',10);
INSERT INTO     my_tab1
VALUES(2,'ABCD',15);
INSERT INTO     my_tab1
VALUES(3,'ABCD',5);
INSERT INTO     my_tab1
VALUES(4,'A123',5);
INSERT INTO     my_tab1
VALUES(5,'A123',10);
INSERT INTO     my_tab1
VALUES(6,'A123',20);
INSERT INTO     my_tab1
VALUES(7,'????',5);
CREATE TABLE     my_tab2
(     workstation     VARCHAR2(4)
,     wkstn_name     VARCHAR2(20)
     CONSTRAINT my_tab2_pk PRIMARY KEY (workstation)
INSERT INTO     my_tab2
VALUES('ABCD','WKSTN 1');
INSERT INTO     my_tab2
VALUES('A123','WKSTN 2');
INSERT INTO     my_tab2
VALUES('B456','WKSTN 3');
CREATE TABLE     my_tab3
(     my_nbr1     NUMBER
,     my_nbr2     NUMBER
INSERT INTO     my_tab3
VALUES(1,2);
INSERT INTO     my_tab3
VALUES(2,3);
INSERT INTO     my_tab3
VALUES(3,4);And, the results I want to get:
workstation     sum(my_value)     wkstn_name     my_nbr1     my_nbr2
ABCD          30          WKSTN 1          1     2
ABCD          30          WKSTN 1          2     3
ABCD          30          WKSTN 1          3     4
A123          35          WKSTN 2          1     2
A123          35          WKSTN 2          2     3
A123          35          WKSTN 2          3     4
B456          0          WKSTN 3          1     2
B456          0          WKSTN 3          2     3
B456          0          WKSTN 3          3     4
????          5          NULL          1     2
????          5          NULL          2     3
????          5          NULL          3     4I've tried a number of different things, googled my problem, and no luck yet...
SELECT     t1.workstation
,     SUM(t1.my_value)
,     t2.wkstn_name
,     t3.my_nbr1
,     t3.my_nbr2
FROM     my_tab1 t1
,     my_tab2 t2
,     my_tab3 t3
...So, what I want is a full outer join of t1 and t2 on workstation, and a cross-join of that with t3. I'm wondering if I can't find any examples of this online because it's not possible....
Note: I'm stuck dealing with Oracle 8i
Thanks!!

Answer 1

Hi,
The query I posted yesterday is a little more complicated than it needs to be.
Since my_tab2.workstation is unique, there's no reason to do a separate sub-query like mt1; we can join my_tab1 to my_tab2 and get the SUM all in one sub-query.
SELECT       foj.workstation
,       foj.sum_my_value
,       foj.wkstn_name
,       mt3.my_nbr1
,       mt3.my_nbr2
FROM       (     -- Begin in-line view foj for full outer join
          SELECT        mt1.workstation
          ,        SUM (mt1.my_value)     AS sum_my_value
          ,        mt2.wkstn_name
          FROM        my_tab1   mt1
          ,        my_tab2   mt2
          WHERE        mt1.workstation     = mt2.workstation (+)
          GROUP BY   mt1.workstation
          ,        mt2.wkstn_name
                UNION ALL
          SELECT      workstation
          ,      0      AS sum_my_value
          ,      wkstn_name
          FROM      my_tab2
          WHERE      workstation     NOT IN (     -- Begin NOT IN sub-query
                                           SELECT      workstation
                                   FROM      my_tab1
                                   WHERE      workstation     IS NOT NULL
                                 )     -- End NOT IN sub-query
       ) foj     -- End in-line view foj for full outer join
,       my_tab3  mt3
ORDER BY  foj.wkstn_name
,       foj.workstation
,       mt3.my_nbr1
,       mt3.my_nbr2
;Thanks for posting the CREATE TABLE and INSERT statements, as well as the very clear desired results!
user11033437 wrote:
... So, what I want is a full outer join of t1 and t2 on workstation, and a cross-join of that with t3. That it, exactly!
The tricky part is how and when to get SUM (my_value). You might approach this by figuring out exactly what my_tab3 has to be cross-joined to; that is, exactly what should the result set of the full outer join between my_tab1 and my_tab2 look like. To do that, take your desired results, remove the columns that do not come from the full outer join, and remove the duplicate rows. You'll get:
workstation     sum(my_value)     wkstn_name
ABCD          30          WKSTN 1          
A123          35          WKSTN 2          
B456          0          WKSTN 3          
????          5          NULL          So the core of the problem is how to get these results from my_tab1 and my_tab2, which is done in sub-query foj above.
I tried to use self-documenting names in my code. I hope you can understand it.
I could spend hours explaining different parts of this query in more detail, but I'm sure I'd waste some of that time explaining things you already understand. If you want an explanation of somthing(s) specific, let me know.