Question

I’ve got a bit of a complicated query that I’m struggling with. You will notice that the schema isn’t the easiest thing to work with but it’s what I’ve been given and there isn’t time to re-design (common story!).

I have rows like the ones below. Note: The 3 digit value numbers are just random numbers I made up.

id     field_id     value
1      5            999 
1      6            888
1      7            777
1      8            foo <--- foo so we want the 3 values above
1      9            don't care

2      5            123 
2      6            456
2      7            789
2      8            bar <--- bar so we DON'T want the 3 values above
2      9            don't care

3      5            623 
3      6            971
3      7            481
3      8            foo <--- foo so we want the 3 values above
3      9            don't care

...
...

n      5            987 
n      6            654
n      7            321
n      8            foo <--- foo so we want the 3 values above
n      9            don't care

I want this result:

id     result
1      999*888*777
3      623*971*481
...
n      987*654*321

Is this clear? So we have a table with n*5 rows. For each of the sets of 5 rows: 3 of them have values we might want to multiply together, 1 of them tells us if we want to multiply and 1 of them we don’t care about so we don’t want the row in the query result.

Can we do this in Oracle? Preferably one query.. I guess you need to use a multiplication operator (somehow), and a grouping.

Any help would be great. Thank you.

Answer 1

something like this:

select m.id, exp(sum(ln(m.value)))
  from mytab m
 where m.field_id in (5, 6, 7)
   and m.id in (select m2.id
                  from mytab m2
                 where m2.field_id = 8
                   and m2.value = 'foo')
 group by m.id;

eg:

SQL> select * from mytab;

        ID   FIELD_ID VAL
---------- ---------- ---
         1          5 999
         1          6 888
         1          7 777
         1          8 foo
         1          9 x
         2          5 123
         2          6 456
         2          7 789
         2          8 bar
         2          9 x
         3          5 623
         3          6 971
         3          7 481
         3          8 foo
         3          9 x

15 rows selected.

SQL> select m.id, exp(sum(ln(m.value))) result
  2    from mytab m
  3   where m.field_id in (5, 6, 7)
  4     and m.id in (select m2.id
  5                    from mytab m2
  6                   where m2.field_id = 8
  7                     and m2.value = 'foo')
  8   group by m.id;

        ID     RESULT
---------- ----------
         1  689286024
         3  290972773