SET NULL not working in SQL*Plus

Question

DB Version: 10.2.0.4
Question1.
Won't SET NULL work with PL/SQL block?
Question2.
Why is <<>> appearing in several lines (one character per line) as shown below? Sorry about the "jive-quote" thing below, got that after i added code tags.
SQL > show lines
linesize 80
SQL > show pages
pagesize 14
SQL > set null <<>>
SQL > select null from dual;
N
<
<
>
>
SQL > set serveroutput on
SQL > declare
  2  v_Val VARCHAR2(100) :='COCOJUMBO';
  3  BEGIN
  4  SELECT null INTO v_val from dual ;
  5  DBMS_output.put_line(v_val);
  6  EXCEPTION
  7  WHEN NO_DATA_FOUND THEN
  8  dbms_output.put_line('Exception:'||SQLERRM);
  9  END;
10  /
PL/SQL procedure successfully completed.
SQL >

Answer 1

user872043 wrote:
DB Version: 10.2.0.4
Question1.
Won't SET NULL work with PL/SQL block?No. SET NULL is a SQL*Plus command, not a PL/SQL command.
Question2.
Why is <<>> appearing in several lines (one character per line) as shown below? Sorry about the "jive-quote" thing below, got that after i added code tags.That's due to default formatting. For example:
SQL> SET NULL <<>>
SQL> SELECT NULL FROM DUAL;
N
<
<
>
>
SQL> COLUMN col FORMAT A4
SQL> SELECT NULL col FROM DUAL;
COL
<<>>