Error while selecting from nested table in PL/SQL block ............

Question

SQL> create type string_table is table of varchar(100);
2 /
Type created.
declare
v_names string_table := string_table();
begin
v_names.EXTEND(3);
v_names(1) := 'name1';
v_names(2) := 'name2';
v_names(3) := 'name3';
dbms_output.put_line(v_names(1));
dbms_output.put_line(v_names(2));
dbms_output.put_line(v_names(3));
dbms_output.put_line(v_names.COUNT());
select * from table(v_names);
end;
select * from table(v_names);
ERROR at line 12:
ORA-06550: line 12, column 7:
PLS-00428: an INTO clause is expected in this SELECT statement

Answer 1

select * from table(v_names);
I guess ,here you were trying to put the content of the NT into another NT, or just trying to print it.
But, I don't think INTO Clause is mandatory here.
Please check your modified code (w/o INTO) and the output :
DECLARE
   TYPE string_table IS TABLE OF VARCHAR (100);
   v_names   string_table := string_table ();
   v_test    string_table := string_table ();
BEGIN
   v_names.EXTEND (3);
   v_names (1) := 'name1';
   v_names (2) := 'name2';
   v_names (3) := 'name3';
   DBMS_OUTPUT.put_line ('Old collection - '||v_names (1));
   DBMS_OUTPUT.put_line ('Old collection - '||v_names (2));
   DBMS_OUTPUT.put_line ('Old collection - '||v_names (3));
   DBMS_OUTPUT.put_line ('Old collection - '||v_names.COUNT ());
   DBMS_OUTPUT.put_line (CHR(10));
   /* SELECT * FROM TABLE (v_names); */
   v_test := v_names;
   DBMS_OUTPUT.put_line ('New collection -- '||v_test (1));
   DBMS_OUTPUT.put_line ('New collection -- '||v_test (2));
   DBMS_OUTPUT.put_line ('New collection -- '||v_test (3));
   DBMS_OUTPUT.put_line ('New collection -- '||v_test.COUNT ());
   DBMS_OUTPUT.put_line (CHR(10));
   /* Printing using FOR LOOP */
   FOR i IN v_test.FIRST..v_test.LAST
   LOOP
     DBMS_OUTPUT.put_line ('In FOR Loop --- '||v_test (i));
   END LOOP;
EXCEPTION
   WHEN OTHERS
   THEN
      DBMS_OUTPUT.put_line ('Error ' ||SQLERRM|| DBMS_UTILITY.format_error_backtrace);
END;gives o/p :
Old collection - name1
Old collection - name2
Old collection - name3
Old collection - 3
New collection -- name1
New collection -- name2
New collection -- name3
New collection -- 3
In FOR Loop --- name1
In FOR Loop --- name2
In FOR Loop --- name3Refer this link -- http://docs.oracle.com/cd/E11882_01/appdev.112/e17126/tuning.htm#CIHGGBGF
Edited by: ranit B on Dec 26, 2012 2:29 PM
-- code modified
Edited by: ranit B on Dec 26, 2012 2:45 PM
-- code 'again' updated -- FOR LOOP added