Segregate the values which are not in Hierarchy ............

Question

Hi All,
Please help me in building the following query:
Parent Child
==== ===
10 20
20 30
30 40
50 60
70 80
etc..... In the above data let us assue there is only one grand parent say 10 and the values 50,60,70,80 etc are not attached to grand parent 10.So i need to display the values which are forgotten to attach to the Top Node 10 i.e, here 50,60,70,80 etc. If my query helps in retreving these values then i can attach them back to the hierarchy.
Thanks in advance.
regards,
kalyan

Answer 1

SQL>WITH t AS
  2       (SELECT 10 AS par, 20 AS chi FROM DUAL UNION ALL
  3        SELECT 20, 30 FROM DUAL UNION ALL
  4        SELECT 30, 40 FROM DUAL UNION ALL
  5        SELECT 50, 60 FROM DUAL UNION ALL
  6        SELECT 70, 80 FROM DUAL)
  7  SELECT *
  8    FROM t
  9   WHERE chi NOT IN(SELECT     chi
10                          FROM t
11                    CONNECT BY PRIOR chi = par
12                    START WITH par = 10);
       PAR        CHI
        50         60
        70         80hth, Urs