Query to find unmatch records

Question

i have 2 tables AHH and ASH. both contain similar columns. primary key on table ASH is based on account number and location id. I want a query to select rows from AHH that are not present in ASH (based on account number and location_id as primary key).
select distinct(h.AHH_N_ACCOUNT_NUM),h.AHH_V_LOCATION_ID from
AHH,ASH
where
(AHH_N_ACCOUNT_NUM <> ASH_N_ACCOUNT_NUM and
AHH_V_LOCATION_ID <> ASH_V_LOCATION_ID)
This query returns all rows in AHH. Can anyone provide me with correct query?

Answer 1

This is other way of doing it:
create table ahh (srl number (3),acc_num number(4),loca_id number(4));
insert into ahh values(1,100,1000);
insert into ahh values(1,200,2000);
insert into ahh values(1,300,3000);
insert into ahh values(1,400,4000);
create table ash (srl number(3),acc_num number(4),loca_id number(4));
insert into ash values(1,100,1000);
insert into ash values(1,200,2000);
select b.acc_num
,b.loca_id
,a.srl
from
     ASH A,
     AHH B
where
A.acc_num(+)=b.Acc_num
and a.loca_id(+)=b.loca_id
and a.srl is not null;
ACC_NUM LOCA_ID SRL
400 4000
300 3000