To get the possible comb'ns through sql query

Question

Hi
I have a table link_details as
sql>select * from link_details;
link_id from_node to_node
1 512 9546
2 546 9129
3 512 9129
4 9546 9234
5 9234 9589
6 9129 9217
7 9589 9900
8 9217 9900
and the from_node and to_node are the FK's which are referenced from the node_id in nodes table.
And now i want to calculate the no'of combinations(Routes, to go from node 512 to node9900) from node 512 to 9900.
I want the o/p like
combination
512-9546-9234-9589-9900
512-9129-9217-9900
Please Help me
Thank you

Answer 1

Well...
I was trying my hands on the problem but could not achieve the end result. I could derive a column, by using ROWNUM, which can be used to group by. Following is what I tried:
SQL> set serveroutput on
SQL> create table link_details (link_id int, from_node number(4), to_node number(4));
Table created
SQL> insert into link_details values (1, 512, 9546);
1 row inserted
SQL> insert into link_details values (2, 546, 9129);
1 row inserted
SQL> insert into link_details values (3, 512, 9129);
1 row inserted
SQL> insert into link_details values (4, 9546, 9234);
1 row inserted
SQL> insert into link_details values (5, 9234, 9589);
1 row inserted
SQL> insert into link_details values (6, 9129, 9217);
1 row inserted
SQL> insert into link_details values (7, 9589, 9900);
1 row inserted
SQL> insert into link_details values (8, 9217, 9900);
1 row inserted
SQL> commit ;
Commit complete
SQL> select * from link_details;
                                LINK_ID FROM_NODE TO_NODE
                                      1       512    9546
                                      2       546    9129
                                      3       512    9129
                                      4      9546    9234
                                      5      9234    9589
                                      6      9129    9217
                                      7      9589    9900
                                      8      9217    9900
8 rows selected
SQL> select max(r) over (order by rownum) rt, ln, from_node, to_node
  2  from (
  3  select decode(ln, lag(ln) over (order by rn) + 1, null, rn) r, ln, from_node, to_node
  4  from (
  5  select rownum rn, level ln, from_node, to_node
  6  from link_details
  7  start with from_node = 512
  8  connect by prior to_node = from_node ) ) ;
RT                                               LN FROM_NODE TO_NODE
1                                                 1       512    9546
1                                                 2      9546    9234
1                                                 3      9234    9589
1                                                 4      9589    9900
5                                                 1       512    9129
5                                                 2      9129    9217
5                                                 3      9217    9900
7 rows selected