String comparision in reverse order

Question

Hi all
i want a logic in plsql which compares string and substring
and soon from last digit in the number to first digit.
If condition mets gives out put
for example my input is
INPUT = 1234567890
TO COMPARE WITH a column has list of values like
1234560000
1234567000
1234567800....soon
so now the condition is
the input 1234567890 should match with the column value
1234567890
if value is not there it should match with
123456789
if not 12345678 soon till 1 in reverse comparision

Answer 1

In SQL:
SQL> ed
Wrote file afiedt.buf
  1  with t as (select '123456' col1 FROM dual)
  2  SELECT col1,inp,lvl FROM
  3  (SELECT SUBSTR(:my_num,1,level-1) inp,level - 1 lvl FROM
  4  dual CONNECT BY level <= LENGTH(:my_num)) x,t
  5* WHERE t.col1 = x.inp
SQL> /
COL1   INP               LVL
123456 123456              6
SQL> ed
Wrote file afiedt.buf
  1  with t as (select '1234567890' col1 FROM dual)
  2  SELECT col1,inp,lvl FROM
  3  (SELECT SUBSTR(:my_num,1,level-1) inp,level - 1 lvl FROM
  4  dual CONNECT BY level <= LENGTH(:my_num) + 1) x,t
  5* WHERE t.col1 = x.inp
SQL> /
COL1       INP               LVL
1234567890 1234567890         10
-- in plsql
SQL> ed
Wrote file afiedt.buf
  1  declare
  2  my_val VARCHAR2(100) := NULL;
  3  BEGIN
  4  FOR I IN REVERSE 1..LENGTH(:my_num) LOOP
  5  DBMS_OUTPUt.PUT_LINE('substring value:'||SUBSTR(:my_num,1,I));
  6  BEGIN
  7  SELECT '123456' INTO my_Val FROM dual WHERE '123456' = SUBSTR(:my_num,1,I);
  8  EXCEPTION
  9  WHEN NO_DATA_FOUND THEN
10  NULL;
11  END;
12  EXIT WHEN my_Val IS NOT NULL;
13  END LOOP;
14  DBMS_OUTPUT.PUT_LINE('matched value:'||my_val);
15* END;
SQL> /
substring value:1234567890
substring value:123456789
substring value:12345678
substring value:1234567
substring value:123456
matched value:123456
PL/SQL procedure successfully completed.
SQL> print :my_num
MY_NUM
1234567890