Yes TamilSelvan..It works.. But it take lengthy time...

select rn from
(select rownum as rn from (
select 1 from dual group by cube (1,1,1,1,1,1,1,1,1,1,1)) a,
(select 1 from dual group by cube (1,1,1,1,1,1,1,1,1,1,1,1)) b)
where rn >=(select min(dadno) from elgidesp.despatchmaster where datype<>2 and daddt>=sysdate-2)
and rn <=(select max(dadno) from elgidesp.despatchmaster where datype<>2 and daddt>=sysdate-2)
minus
select to_number(dadno) from elgidesp.despatchmaster where datype<>2 and daddt>=sysdate-2

Elapsed Time: 00:00:40.38

Is any opttion to reduce...???
Any Index Problem...???