Expanding possible scenarios in a view

Question

Hi,
I'm trying to expand out business rules which use a 'one of this group and one of this group...' type logic e.g.:
there are 3 groups:
in the first group are 2 options
in the second group there are 3 options
in the third group there are 3 options
I need my end result to be a full set of data for every scenario:
Scenario Group Option
1 1 a
1 2 a
1 3 a
2 1 a
2 2 a
2 3 b
3 1 a
3 2 a
3 3 c
4 1 a
4 2 b
4 3 a
currently I have managed to create the correct number of rows for each option for each scenario, but I can not devise a way of ordering them to give the 'Scenario' column in the above example.
Any help would be most appreciated. If more info is needed, please let me know.
Thanks,
Julian

Answer 1

Hi, Julian,
Welcome to the forum!
905015 wrote:
Hi,
I'm trying to expand out business rules which use a 'one of this group and one of this group...' type logic e.g.:
there are 3 groups:
in the first group are 2 optionsIn the output below, it looks like 'a' is the only option when grp=1. (GROUP is not a good column name.)
in the second group there are 3 optionsAgain, it looks like there are only 2 options, 'a' and 'b', for grp=2.
in the third group there are 3 options
I need my end result to be a full set of data for every scenario:
Scenario Group Option
1 1 a
1 2 a
1 3 a
2 1 a
2 2 a
2 3 b
3 1 a
3 2 a
3 3 c
4 1 a
4 2 b
4 3 aWhat is a "scenario" in this problem?
Why do you not want, for example:
Scenario     Grp     Option
5          1     a
5          2     b
5          3     b     ?
currently I have managed to create the correct number of rows for each option for each scenario, but I can not devise a way of ordering them to give the 'Scenario' column in the above example.
Any help would be most appreciated. If more info is needed, please let me know.As Newbie said, post CREATE TABLE and INSERT statements for your sample data, and the results you want from that data (if they are not exactly what you posted already.)
Explain how you get those results from that data.
Always say which version or Oracle you're using.
You can get all combinations (one item from grp=1, one from grp=2 and one from grp=3) like this:
SELECT  ROW_NUMBER () OVER (ORDER BY NULL)     AS scenario
,       SYS_CONNECT_BY_PATH (option, '/')     AS option_list
FROM     table_x
WHERE     CONNECT_BY_ISLEAF     = 1
START WITH     grp     = 1
CONNECT BY     grp     = 1 + PRIOR grp
;This will produce one row per combination (perhaps that's what you mean by "scenario") like this:
SCENARIO     OPTION_LIST
1          /a/a/a
2          /a/a/b
3          /a/a/c
4          /a/b/a
...If you want a separate output row for each combination and grp, then you can split apart the option_list like this:
WITH     got_option_list          AS
     SELECT  ROW_NUMBER () OVER (ORDER BY ROWNUM)     AS scenario
     ,       SYS_CONNECT_BY_PATH (option, '/')     AS option_list
     FROM     table_x
     WHERE     CONNECT_BY_ISLEAF     = 1
     START WITH     grp     = 1
     CONNECT BY     grp     = 1 + PRIOR grp
     ORDER SIBLINGS BY     option
,     all_groups     AS
     SELECT DISTINCT     grp
     FROM          table_x
SELECT       o.scenario
,       g.grp
,       REGEXP_SUBSTR ( option_list
                      , '[^/]+'
                     , 1
                     , g.grp
                     )          AS option
FROM          got_option_list     o
CROSS JOIN     all_groups     g
ORDER BY  o.scenario
,       g.grp
;Of course, since I don't have your table, I can't actually test this.
Notice that this solution does not assume you know how many options are in the different grps. It doesn't even assume you know how many grps there are. It does assume that the groups are numbered with consecutive integers, starting with 1. If that's not the case, use the analytic DENSE_RANK function to map the actual grp values (they don't have to be NUMBERs) to 1, 2, 3, ...