DECLARE
  a VARCHAR2(5):=0;
  b VARCHAR2(5):=0;
  c VARCHAR2(5):=0;
PROCEDURE p1(
    p_str VARCHAR2)
IS
BEGIN
  IF a=0 THEN
    dbms_output.put_line('in A');
  END IF;
  IF b=0 THEN
    dbms_output.put_line('in b');
  END IF;
  IF c=0 THEN
    dbms_output.put_line('in c');
  END IF;
END;
BEGIN
  --which conditions need to be checked.
  p1('a,b,c');
  p1('a,b');
END;

create or replace PROCEDURE p1( p_str VARCHAR2)
IS

a VARCHAR2(5):=0;
  b VARCHAR2(5):=0;
  c VARCHAR2(5):=0; 
BEGIN
  IF instr ('a,b,c','a')>0 THEN
    dbms_output.put_line('in A');
  END IF;
  IF instr ('a,b,c','b')>0 THEN
    dbms_output.put_line('in b');
  END IF;
  IF instr ('a,b,c','c')>0 THEN
    dbms_output.put_line('in c');
  END IF;
END;  

declare
v1 varchar2(10):='asha';
v2 varchar2(10);
v3 varchar2(10);
begin
v2:='v1';
select v2 into v3 from dual ;
dbms_output.put_line(v3);
end;

create table test1
(v1 varchar2(10));

insert into test1 values('asha');

declare
v1 varchar2(10):='asha';
v2 varchar2(10);
v3 varchar2(10);
str varchar2(50);
c1 sys_refcursor;
begin
v2:='v1';
str:='select '||v2|| ' from test1';
dbms_output.put_line(str);
open c1 for str;
fetch c1 into v3;
dbms_output.put_line(v3);
close c1;
end;