Dynamic column selection

Question

I want to select specific columns from a table dynamically which are basically the columns returned by quering the user_tab_columns data dictionary which in turn has to satisfy certain condition for me.
So, what I want to do is something like:
SELECT b.(dynamic column list from a)
FROM b,
(SELECT column_name FROM user_tab_columns WHERE table_name='STH' AND ........) a
any help will be greatly appreciated.

Answer 1

sql>create or replace procedure p_dynamic_sql
  2  is
  3    v_sql varchar2(4000);
  4  begin
  5    v_sql := 'select ';
  6    for r in (select column_name
  7                from user_tab_cols
  8               where table_name = 'EMP'
  9                 and column_name like 'E%') loop
10      v_sql := v_sql || r.column_name || ',';
11    end loop;
12    v_sql := rtrim(v_sql, ',') || ' from emp';
13    dbms_output.put_line( v_sql );
14    -- do something with SQL (open cursor, etc.)   
15  end;
16  /
Procedure created.
sql>exec p_dynamic_sql
select EMPNO,ENAME from emp
PL/SQL procedure successfully completed.