Reverse function in pl/sql

Question

Hi,
Please help me.
How to use reverse funtion in pl/sql block (Oracle 8).
My Example which gives error.
Declare
A Varchar2(10);
Begin
Select Reverse('vijay') into A From Dual;
Dbms_output.Put_line(' Reverse Value '||A);
End;
Thanking You,
Regards.

Answer 1

REVERSE works in PL/SQL in 9i only (works fine in SQL below 9i).
In versions below 9i, you can use Dynamic SQL,
or create your own function.
I ran this in 9i:
SQL> Declare
  2       A Varchar2(10);
  3  Begin
  4       Select Reverse('vijay') into A From Dual;
  5       Dbms_output.Put_line(' Reverse Value '||A);
  6  End;
  7  /
Reverse Value yajiv
PL/SQL procedure successfully completed.Here's a function you can use in 8i and below:
CREATE OR REPLACE FUNCTION reverse_string(string_in VARCHAR2)
RETURN VARCHAR2 AS
        v_new_string    VARCHAR2(4000);
        v_length        PLS_INTEGER := NVL(LENGTH(string_in),0);
BEGIN
        FOR i IN REVERSE 1..v_length
        LOOP
             v_new_string := v_new_string ||
                            SUBSTR(string_in, i, 1);
        END LOOP;
   RETURN v_new_string;
END reverse_string;
Function created.
Declare
     A Varchar2(10);
Begin
     Select reverse_string('vijay') into A From Dual;
     Dbms_output.Put_line(' Reverse Value '||A);
End;
Reverse Value yajiv
PL/SQL procedure successfully completed.