MIN by CASE (HELP)

Question

TABLE A
ID     TERM     UNITED
1     604     LOP
1     604     MA
9     704     SC
9     603     CI
9     704     BPO
3     603     LOS
2     603     KIR
1     603     SSK
1     602     MNO
TABLE B
ID     CITY
1     (null)
1     (null)
9     603
9     603
9     603
3     (null)
2     (null)
1     (null)
1     (null)
I WANT:
ID     TERM
1     604
9     (null)
3     603
2     603
1     602
So where there is a UNITED and NO CITY then display lowest TERM.
BUT IF there IS A UNITED AND CITY then NULL (eg ID 9)
What i had:
SELECT A.ID, min(A.TERM) as TERM
FROM TABLE A, TABLE B
WHERE A.ID = B.ID
AND A.UNITED IS NOT NULL
AND B.CITY IS NULL
GROUP BY A.ID
ORDER BY A.ID
which gets me:
ID     TERM     UNITED     CITY
1     604     LOP     (null)
1     604     MA     (null)
1     603     LOS     (null)
3     603     KIR     (null)
2     603     SSK     (null)
1     602     MNO     (null)
It Does not disply ID 99999
I know why but i dont know how to ad a case statement to bypass it.
Can any one help?
Thank you.
Edited by: 927374 on 12/04/2012 23:11
Edited by: 927374 on 12/04/2012 23:13
Edited by: 927374 on 12/04/2012 23:14

Answer 1

I am not sure why you expect this row :
ID     TERM
1     604Shouldn't the lowest TERM for ID 1 be 602 ?
may be :
SQL> ed
Wrote file afiedt.buf
  1  with tab_a as
  2  (
  3  select 1 ID, 604 term, 'LOP' united from dual union all
  4  select 1, 604, 'MA' from dual union all
  5  select 9, 704, 'SC' from dual union all
  6  select 9, 603, 'CI' from dual union all
  7  select 9, 704, 'BPO' from dual union all
  8  select 3, 603, 'LOS' from dual union all
  9  select 2, 603, 'KIR' from dual union all
10  select 1, 603, 'SSK' from dual union all
11  select 1, 602, 'MNO' from dual
12  ),
13  tab_b as
14  (
15  select 1 id, null city  from dual union all
16  select 1, null  from dual union all
17  select 9, 603 from dual union all
18  select 9, 603 from dual union all
19  select 9, 603 from dual union all
20  select 3, null from dual union all
21  select 2, null  from dual union all
22  select 1, null  from dual union all
23  select 1, null  from dual
24  )
25  select id,
26         min(term) term
27  from   (select a.id,
28                 a.united,
29                 Nvl2(b.city, min(null), min(a.term)) term
30          from   tab_a a,
31                 tab_b b
32          where  a.id = b.id
33          group  by a.id,
34                    a.united,
35                    b.city
36          order  by a.id)
37* group  by id
SQL> /
        ID TERM
         1 602
         2 603
         3 603
         9
4 rows selected.