Exception too many rows...

Question

Hi
I am getting two different outputs with following code depending upon i declare the variable in first or second way...
when i declare the variable v_empno as number(10) and too many rows exception is raised....and after that i dbms this variable..it is null...
but when i declare the same variable as table.column%type....and the similar scenario happens and i dbms the value of variable...it is not null...rather the first value from output of the query...
declare
--v_empno number(10);
v_empno emp.empno%type;
begin
dbms_output.put_line('before '||v_empno );
select empno into v_empno from emp;
dbms_output.put_line('first '||v_empno);
exception when too_many_rows then
dbms_output.put_line('second '||v_empno);
dbms_output.put_line('exception'||sqlerrm);
end;
is there any specific reason for this....
ur comments plz
Thanks
Sidhu

Answer 1

In 9i:
SQL> declare
  2  --v_empno number(10);
  3  v_empno emp.empno%type;
  4  begin
  5  dbms_output.put_line('before '||v_empno );
  6  select empno into v_empno from emp;
  7  dbms_output.put_line('first '||v_empno);
  8  exception when too_many_rows then
  9  dbms_output.put_line('second '||v_empno);
10  dbms_output.put_line('exception'||sqlerrm);
11  end;
12  /
before
second 7369
exceptionORA-01422: exact fetch returns more than requested number of rows
PL/SQL procedure successfully completed.
SQL> declare
  2  v_empno number;
  3  --v_empno emp.empno%type;
  4  begin
  5  dbms_output.put_line('before '||v_empno );
  6  select empno into v_empno from emp;
  7  dbms_output.put_line('first '||v_empno);
  8  exception when too_many_rows then
  9  dbms_output.put_line('second '||v_empno);
10  dbms_output.put_line('exception'||sqlerrm);
11  end;
12  /
before
second
exceptionORA-01422: exact fetch returns more than requested number of rows
PL/SQL procedure successfully completed.
SQL> edit
Wrote file afiedt.buf
  1  declare
  2  v_empno number(10);
  3  --v_empno emp.empno%type;
  4  begin
  5  dbms_output.put_line('before '||v_empno );
  6  select empno into v_empno from emp;
  7  dbms_output.put_line('first '||v_empno);
  8  exception when too_many_rows then
  9  dbms_output.put_line('second '||v_empno);
10  dbms_output.put_line('exception'||sqlerrm);
11* end;
SQL> /
before
second 7369
exceptionORA-01422: exact fetch returns more than requested number of rows
PL/SQL procedure successfully completed.In 10G:
SQL> declare
  2  v_empno number(10);
  3  --v_empno emp.empno%type;
  4  begin
  5  dbms_output.put_line('before '||v_empno );
  6  select empno into v_empno from emp;
  7  dbms_output.put_line('first '||v_empno);
  8  exception when too_many_rows then
  9  dbms_output.put_line('second '||v_empno);
10  dbms_output.put_line('exception'||sqlerrm);
11  end;
12  /
before
second 7369
exceptionORA-01422: exact fetch returns more than requested number of rows
PL/SQL procedure successfully completed.
SQL> edit
Wrote file afiedt.buf
  1  declare
  2  v_empno number;
  3  --v_empno emp.empno%type;
  4  begin
  5  dbms_output.put_line('before '||v_empno );
  6  select empno into v_empno from emp;
  7  dbms_output.put_line('first '||v_empno);
  8  exception when too_many_rows then
  9  dbms_output.put_line('second '||v_empno);
10  dbms_output.put_line('exception'||sqlerrm);
11* end;
SQL> /
before
second 7369
exceptionORA-01422: exact fetch returns more than requested number of rows
PL/SQL procedure successfully completed.
SQL> edit
Wrote file afiedt.buf
  1  declare
  2  --v_empno number;
  3  v_empno emp.empno%type;
  4  begin
  5  dbms_output.put_line('before '||v_empno );
  6  select empno into v_empno from emp;
  7  dbms_output.put_line('first '||v_empno);
  8  exception when too_many_rows then
  9  dbms_output.put_line('second '||v_empno);
10  dbms_output.put_line('exception'||sqlerrm);
11* end;
SQL> /
before
second 7369
exceptionORA-01422: exact fetch returns more than requested number of rows
PL/SQL procedure successfully completed.Anyhow you should not rely on the fact Oracle fetches the first value into variable
and keeps it when the excaprion is raised.
Tom Kyte discusses the SELECT INTO issue here:
http://asktom.oracle.com/pls/ask/f?p=4950:8:7849913143702726938::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:1205168148688
Rgds.