Select statement or a procedure or a function required for this requirement

Question

i have 2 tables t1 and t2.
t1 contains 1 column,named as c_id
t2 contains 2 columns, named as tc_id and preceeding_c_id.
select * from t1;
c_id
100
200
300
400
select * from t2;
tc_id preceeding_c_id
150 100
180 150
100
190 180
210 200
250 210
260 250
Now my requirement is:
I need to send a parameter as :c_id = 100
the ouput should be as follows
100
150
180
190
:c_id = 200
the output should be as follows:
200
210
250
260
Thanks & Regards

Answer 1

SQL> variable c_id number
SQL> exec :c_id := 100
PL/SQL procedure successfully completed.
SQL> with t as (
  2             select 150 tc_id, 100 preceeding_c_id from dual union all
  3             select 180, 150 from dual union all
  4             select 100, null from dual union all
  5             select 190, 180 from dual union all
  6             select 210, 200 from dual union all
  7             select 250, 210 from dual union all
  8             select 260, 250 from dual
  9            )
10   select  tc_id
11     from  t
12     start with preceeding_c_id = :c_id
13     connect by preceeding_c_id = prior tc_id
14  union all
15   select  :c_id
16     from  dual
17  order by 1
18  /
     TC_ID
       100
       150
       180
       190
SQL> exec :c_id := 200
PL/SQL procedure successfully completed.
SQL> /
     TC_ID
       200
       210
       250
       260
SQL> SY.