[charushila]

you can use outer join for missing rows.operator + is used for that. you can use it as left or right join. if you want records of two tables and if there is no match in bet them.
e.g
select e.last_name,e.dept_id ,d.dept_name
from employees e,department d
where e.dep_id(+)=d.dept_id

i hope this will do.