sum with null value

Hi! I've got problem with sql statement..

in dataset like
col1 col2

a        1
b        3
c        5
d        null
e        2

i must to sum col2, but if 1 single value of this column is null then sum must result to null, according this i wrote statement:

select sum(col2) from table1

but this query results with 11.

any idea??!!

create table table1 (col1 char(1), col2 number);

insert into table1 values('a',1);

insert into table1 values('b',3);

insert into table1 values('c',5);

insert into table1 values('d',null);

insert into table1 values('e',2);

commit;

select sum(col2) from table1; Received on Mon Aug 28 2006 - 05:59:35 CDT