User Defined function in Where clause

Question

DB:- 11.2
Input:- 'ACCOUNTING,SALES'
Output:- ('ACCOUNTING','SALES')
WITH T AS (select 'ACCOUNTING,SALES' str from dual)
select '('||regexp_replace(str,'([[:alpha:]]+)','''\1''')||')' from t /*this works*/I've created a function to use this in a where clause
create or replace function ss(dname varchar2)
return varchar2 is
begin
  RETURN '('||regexp_replace(dname,'([[:alpha:]]+)','''\1''')||')';
end; 
select ss('ACCOUNTING,SALES') from dual --this worksBut when I am using this function in a where clause result is not coming..any thing i am missing?
select * from dept where dname in ss('ACCOUNTING,SALES') --no rows

Answer 1

940838 wrote:
Output:- ('ACCOUNTING','SALES')Wrong. ('ACCOUNTING','SALES') is a list of two strings 'ACCOUNTING' and 'SALES' while your function returns a single string '(''ACCOUNTING'',''SALES'')'.
IN clause requires a comma-separated list of values while your function, again, returns just one value. So query is comparing 'SALES' whith '(''ACCOUNTING'',''SALES'')', not with ('ACCOUNTING','SALES') and obviously no match. What you are trying to do is called dynamic SQL. There are plenty examples on how to use it. But you don't need it. Use nested table or varray. I'll use Oracle supplied varray type sys.OdciVarchar2List:
select  *
  from  dept
  where dname in (
                  select  *
                    from  table(sys.OdciVarchar2List('ACCOUNTING','SALES'))
    DEPTNO DNAME          LOC
        10 ACCOUNTING     NEW YORK
        30 SALES          CHICAGO
SQL>SY.